Synthesis of cephalosporin compounds

ABSTRACT

Provided herein is a method for the synthesis of cephalosporin antibiotic compounds comprising a palladium-catalyzed coupling reaction.

1. CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Division of U.S. Ser. No. 15/503,907, filed Feb.14, 2017, now U.S. Pat. No. 10,125,149, which is a U.S. National Phaseapplication under 35 U.S.C. § 371 of PCT Application No.PCT/US2015/045287, filed Aug. 14, 2015, which claims priority under 35U.S.C. § 119(e) from U.S. Ser. No. 62/037,676, filed Aug. 15, 2014, U.S.Ser. No. 62/065,993, filed Oct. 20, 2014, and U.S. Ser. No. 62/111,840filed Feb. 4, 2015, the contents of which are incorporated herein byreference in their entireties.

2. TECHNICAL FIELD

The present disclosure relates to the synthesis of cephalosporins via apalladium catalyzed coupling reaction.

3. BACKGROUND

Cephalosporin compounds containing the chemical substructure of formula(I) are important antibacterial therapeutic agents. The manufacture ofseveral known cephalosporin compounds involves forming new bonds at anallylic carbon indicated by C¹ in the structure below:

This allylic moiety is found, for example, in ceftolozane, acephalosporin antibacterial agent, also referred to as CXA-101,FR264205, or by chemical names such as(6R,7R)-3-[(5-amino-4-([(2-aminoethyl)carbamoyl]amino)-1-methyl-1H-pyrazol-2-ium-2-yl)methyl]-7-({(2Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-[(1-carboxy-1-methylethoxy)imino]acetyl}amino)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate,and7β-[(Z)-2-(5-min-1,24-thiadiazol-3-yl)-2-(1-carboxy-1-methylethoxyimino)acetamido]-3-{3-amino-4-[3-(2-aminoethyl)ureido]-2-methyl-1-pyrazolio}methyl-3-cephem-4-carboxylate.Ceftolozane sulfate is a pharmaceutically acceptable ceftolozane salt ofcompound (VII), that can be formulated for intravenous administration orinfusion.

Ceftolozane can be obtained using methods described in U.S. Pat. Nos.7,129,232 and 7,192,943, as well as Toda et al., “Synthesis and SAR ofnovel parenteral anti-pseudomonal cephalosporin's: Discovery ofFR264205.” Bioorganic & Medicinal Chemistry Letters, 18, 4849-4852(2008), each of which are incorporated herein by reference in theirentirety. These methods are illustrated in FIGS. 1A and 1B.

There remains a need to identify novel manufacturing processes forsynthesizing cephalosporin compounds comprising the chemicalsubstructure of formula (I) such as, for example, ceftolozane.

4. SUMMARY

Provided herein are methods for the synthesis of cephalosporin compoundsof formula (I) employing a palladium-catalyzed alkylation reaction, aswell as compositions related to the same.

In an aspect, provided herein is a method for preparing a compound offormula (II), or a salt thereof.

comprising the step of admixing. e.g., reacting, a compound of formula(III), or a salt thereof,

with a nucleophile (Nuc) in the presence of reagents comprising: (a) apalladium source; and (b) a palladium-binding ligand, to form a compoundof formula (II), or a salt thereof.

In another aspect, provided herein is a composition comprising acompound of formula (Va) and palladium.

In another aspect, provided herein is a method for preparing a compoundof formula (VII):

or a salt thereof, comprising the step of admixing, e.g., reacting, acompound of formula (IX)

or a salt thereof, with a nucleophile (Nuc)(e.g., R⁴-M) in the presenceof reagents comprising: (a) a palladium source and (b) apalladium-binding ligand, to form a compound of formula (VIII), or asalt thereof.

The nucleophile, palladium source, palladium-binding ligand, andvariables of compounds of formulae (II), (III), (VIII) and (IX) aredefined herein.

In some embodiments, the method comprises removal of palladium.

In some embodiments, the method comprises recovery of palladium.

5. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is an example synthetic scheme showing known methods ofceftolozane synthesis (See. e.g., U.S. Pat. Nos. 7,129,232 and7,192,943, as well as Toda et al., “Synthesis and SAR of novelparenteral anti-pseudomonal cephalosporins: Discovery of FR264205.”Bioorganic & Medicinal Chemistry Letters, 18, 4849-4852 (2008)).

FIG. 1B is a synthetic scheme for preparing a ceftolozane startingmaterial, a protected 5-amino-1-methylpyrazole. (See. e.g., Toda et al.,“Synthesis and SAR of novel parenteral anti-pseudomonal cephalosporins:Discovery of FR264205,” Bioorganic & Medicinal Chemistry Letters. 18,4849-4852 (2008)).

FIG. 2 is a reference ¹H NMR spectrum of isolated ceftolozane TFA.

FIG. 3 is an HPLC chromatograph of compound 3z. A major peak at 9.552min is shown.

FIG. 4 is an HPLC chromatograph of the reaction admixture to formcompound 5taz from compound 3taz, after 15 minutes of reaction time. Amajor peak at 1.777 min is shown.

6. DETAILED DESCRIPTION

Provided herein are methods of using palladium catalysis forsubstitution of the C¹ position of compounds of formula (I), and relatedcompositions.

The methods provided herein offer several advantages over the methodspreviously disclosed, including higher yields, higher purity, fasterreaction time, and use of lower amounts of solid reagents compared to,for example, the analogous reaction for the conversion of compound 3 tocompound 5a as shown in FIG. 1A.

In one aspect, provided herein is a method for preparing a compound offormula (II):

or a salt thereof comprising the step of admixing. e.g., reacting, acompound of formula (III)

or a salt thereof, with a nucleophile (Nuc)(e.g., R-M) in the presenceof reagents comprising:

(a) a palladium source; and

(b) a palladium-binding ligand;

to form a compound of formula (II), or a salt thereof.

The nucleophile, palladium source, palladium-binding ligand, andvariables of compounds of formulae (II) and (III) are defined below.

Nucleophile (Nuc)

Nucleophiles include carboxylic acid, alcohols, water, amides, ureas,thiols, N-containing heteroaryls (e.g., optionally substitutedpyrazoles) and N-containing heterocycles. These nucleophiles can be usedin an anionic form, e.g. as carboxylates, hydroxides, and alkoxides.

In an embodiment, Nuc is R⁴-M, wherein

M is H, a metal cation, a non-metal cation, or lone pair of electrons;and

R⁴ is selected from the group consisting of carboxylates, hydroxides,alkoxides, ureas, N-containing heteroaryls and N-containingheterocycles, wherein said carboxylates, alkoxides, thiolates.

N-containing heteroaryls and N-containing heterocycles are optionallysubstituted.

M can be a metal selected from, for example, alkali metals, alkalineearth metals, transition metals, and main group metals. For metalcations having a formal charge greater than one (e.g., 2), more than oneequivalent of R⁴ will be present in the Nuc (e.g., (R⁴)₂M).

One skilled in the art will recognize that the formal charge of Rchanges when a lone pair reacts to form a bond.

In one embodiment, M is H, a metal cation or a non-metal cation, and R⁴is selected from the group consisting of:

In another embodiment, M is H and R⁴-M is selected from the groupconsisting of

In another embodiment, M is a lone pair of electrons and R⁴-M is:

In still another embodiment. M is a lone pair of electrons and R⁴-M is acompound of formula (X):

wherein R⁵ is a nitrogen protecting group; and R⁶ is a nitrogenprotecting group.

In some embodiments, the compound of formula (X) has the structure offormula (UBT):

An example of the synthesis of this nucleophile, a protected4-amino-5-amino-1-methylpyrazole, is found in FIG. 1B.

Variable LG

LG is a leaving group. In certain embodiments. LG is halo.—O(C═O)N(R¹⁸)₂. —O(C═O)OR¹⁸ and —OC(O)R¹⁸, wherein R¹⁸ is independentlyin each instance selected from the group consisting of C₁₋₆ alkyl andhaloalkyl (e.g., —CF₃). In certain embodiments. LG is halo or —OC(O)R¹⁸,wherein R¹⁸ is selected from the group consisting of C₁₋₆ alkyl andhaloalkyl (e.g., —CF₃). In a particular embodiment, LG is chloride or—OC(O)CF₃. In some embodiments, the haloalkyl is a C₁₋₆ haloalkyl.

Variable R¹

In certain embodiments. R¹ is R^(1′)—Z; wherein R^(1′) is selected fromthe group consisting of a bond, aryl, cycloalkyl, cycloalkenyl,heterocyclyl, and heteroaryl; wherein Z is 1-2 instances of asubstituent that for each occurrence is independently selected from thegroup consisting of hydrogen, halogen, hydroxyl, hydroxyalkyl,aminoalkyl, alkyl, alkylidenyl, alkenyl, heteroalkyl, cyano and amino,wherein Z is optionally, independently substituted one or more timeswith amino, halogen, carboxyl, carboxamide, oxo, a nitrogen protectinggroup, an oxygen protecting group or —P(O)(OZ′)₂; and wherein Z′ isindependently hydrogen or an oxygen protecting group.

In one embodiment. R¹ is selected from the group consisting of aryl andheteroaryl moieties. In certain embodiments. R¹ is a substituted orunsubstituted aryl or heteroaryl moiety selected from the groupconsisting of: thiophene, furan thiazole, tetrazole, thiadiazole,pyridyl, phenyl, phenol, cyclohexadiene and dithietane. In a particularembodiment, R¹ is selected from the group consisting of the followingmoieties:

and salts thereof wherein Z′ is as defined herein. In some embodiments,R¹ is selected from the group consisting of:

In some embodiments. R¹ is

In a particular embodiment, R¹ is

In another particular embodiment, R¹ is

In some embodiments, Z′ is a C₁₋₆ alkyl, such as Me, Et, or tert-butyl.In some embodiments. Z′ is abase-labile oxygen protecting group, such asbut not limited to —COMe, —COEt, and —(CO)-propyl. In some embodiments.Z′ is an oxygen protecting group that is removed under reductiveconditions. e.g., catalytic hydrogenation, such as benzyl. In someembodiments, Z′ is an acid-labile oxygen protecting group, such as butnot limited to tert-butyl 4-methoxybenzyl, 2-methoxybenzyl, ortriphenylmethyl, preferably tert-butyl.

Variable R²

In certain embodiments. R² is selected from the group consisting ofhydrogen and alkoxy. In a particular embodiment of the method, R² ishydrogen.

Variable Y

In certain embodiments. Y is selected from the group consisting of abond, CH₂, CH₂S, SCH₂. C═C(H)CH₂CO₂R′. CH(OR′), C═N(OR′). CHN(R″) andC═NR″; wherein R′ is selected from the group consisting of hydrogen, anoxygen protecting group and alkyl, wherein the alkyl is optionallysubstituted one or more times with halogen, hydroxyl or —CO₂R¹⁵; whereinR″ is a substituent that for each occurrence is selected from hydrogen,alkyl, C(O)heterocyclyl, and a nitrogen protecting group, wherein anytwo R″ substituens may combine to form a ring or a single nitrogenprotecting group; and wherein R¹⁵ is independently hydrogen or an oxygenprotecting group.

In some embodiments. R′ is a C₁₋₆ alkyl, such as Me. Et, or tert-butyl.In some embodiments R′ is abase-labile oxygen protecting group, such asbut not limited to —COMe, —COEt, and —(CO)-propyl. In some embodiments.R′ is an oxygen protecting group that is removed under reductiveconditions. e.g., catalytic hydrogenation, such as benzyl. In someembodiments. R′ is an acid-labile oxygen protecting group, such as butnot limited to tert-butyl, 4-methoxybenzyl, 2-methoxybenzyl, ortriphenyhmethyl, preferably tert-butyl.

In some embodiments, Y is selected from the group consisting of —CH₂—,

In one embodiment of the method, Y is selected from a bond, CH₂, CH₂Sand C═C(H)CH₂CO₂R′, and R′ is selected from the group consisting ofhydrogen and an oxygen protecting group. In another embodiment, Y isC═N(OR′) and R′ is selected from the group consisting of an oxygenprotecting group, hydrogen, methyl, ethyl. CH₂CO₂R¹⁵ and C(CH₃)₂CO₂R¹⁵.In yet another embodiment, Y is CH(OR′) and R′ is hydrogen or an oxygenprotecting group. In still another embodiment Y is CHN(R″)₂ and R″, foreach occurrence, is independently selected from hydrogen, a nitrogenprotecting group and

In a particular embodiment. Y is C═N(OR′) and R′ is C(CH₃)₂CO₂ ^(t)Bu.

In some embodiments. Y is

Variable R³

In certain embodiments, R³ is selected from the group consisting ofhydrogen and an oxygen protecting group.

In some embodiments. R³ is a C₁₋₆ alkyl, such as Me. Et, or tert-butyl.In some embodiments. R³ is a base-labile oxygen protecting group (i.e.,one that is removed under basic conditions), such as but not limited toMe. Et, and propyl. In some embodiments. R³ is a protecting group thatcan be removed under hydrogenation conditions, such as benzyl. In someembodiments. R³ is an acid-labile oxygen protecting group (i.e., onethat is removed under acid conditions), such as but not limited totert-butyldimethylsilyl, tert-butyl, 4-methoxybenzyl, 2-methoxybenzyl,or triphenylmethyl.

In another embodiment of the method, R³ is an oxygen protecting groupselected from benzyl ethers. Benzyl ethers may be substituted (e.g.,with one or more alkoxy substituents) or unsubstituted. In a particularembodiment, R³ is

(i.e., 4-methoxybenzyl, PMB, MPM).

Variable R⁴

R⁴ is the radical resulting from addition of the Nuc (e.g., R⁴-M) asdescribed below.

In an embodiment, R⁴ is carboxyl, hydroxyl, alkoxy, urea, urea adduct,N-containing heteroaryl or N-containing heterocyclyl, wherein saidcarboxyl, alkoxy, N-containing heteroaryl and N-containing heterocyclylare optionally substituted.

In some embodiments, R⁴ is a N-containing heteroaryl (i.e.,nitrogen-containing heteroaryl, or a heteroaryl containing at least onenitrogen in the ring). Nitrogen-containing heteroaryls include but arenot limited to pyrazoles, pyrroles, triazoles, pyridines, pyrimidines,thiazoles, and thiadiazoles, each of which can be optionallysubstituted. In some embodiments, R⁴ is a pyrazole, pyrrole, triazole,or pyridine, which are each optionally substituted. In some embodiments,R⁴ is a pyrazole or a pyridine, which are each optionally substituted.In some embodiments, R⁴ is an unsubstituted pyridine. In someembodiments, the N-containing heteroaryl is attached to the rest of thecompound of formula (II) through the heteroaryl ring N atom (i.e., aring N-linked nitrogen-containing heteroaryl).

In an embodiment, R⁴ is selected from the group consisting of

wherein R⁵ is a nitrogen protecting group; and R⁶ is a nitrogenprotecting group.

In one embodiment, R⁴ is:

In some embodiments. R⁴ is a substituted pyrazole. In some embodiments.R⁴ is a substituted pyrazole that has one, two, three, or foursubstituents. In some embodiments. R⁴ is a pyrazole substituted with aC₁₋₆ alkyl. In some embodiments, R⁴ is a pyrazole substituted with aurea. In some embodiments. R⁴ is a pyrazole substituted with an amine.

In an embodiment. R⁴ is

which is the result of addition of Nuc (i.e., R⁴-M, wherein M is lonepair of electrons), e.g., a compound of formula (X):

In some embodiments, R⁵ is an acid-labile nitrogen protecting group. Insome embodiments. R⁵ is tert-butyloxycarbonyl.

In some embodiments, R⁶ is an acid-labile nitrogen protecting group. Insome embodiments, R⁶ is triphenylmethyl.

In some embodiments. R⁵ and R⁶ are each independently an acid-labilenitrogen protecting group. In some embodiments. R⁵ and R⁶ are eachindependently triphenylmethyl, tert-butyl, tert-butoxycarbonyl,2-trimethylsilylethoxycarbonyl, or 4-methoxybenzyloxycarbonyl. In anembodiment, R⁵ is tert-butyloxycarbonyl and R⁶ is triphenylmethyl.

In an embodiment, R′ is tert-butyl; R³ is 4-methoxy benzyl ether (i.e.,4-methoxybenzyl); R⁵ is tert-butyloxycarbonyl; and R⁶ istriphenyhoethyl.

In some embodiments, the compound of formula (II) has the structure offormula (II′):

wherein R¹, R², R³. R⁴, and R′ are as described herein.

Palladium Source

The term “palladium source” indicates a source of palladium. In someembodiments, the palladium source is any source that is known tofacilitate palladium π-allyl chemistry, including but not limited tosolvent-soluble palladium catalysts and palladium on solid support, suchas palladium(0) on carbon black powder. Solvent-soluble palladiumcatalysts include palladium(II) catalysts, such asbis(acetonitrile)dichloropalladium(II),bis(acetylacetonate)palladium(II), bis(benzonitrile)palladium(II)chloride, bis(dibenzylideneacetone)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, allylpalladium(II) chloride dimer,palladium(II) chloride, palladium(II) bromide,tetrakis(acetonitrile)palladium(II) tetrafluoroborate,[1,2-bis(diphenylphosphino)ethane] dichloropalladium(II),1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloridedichloromethane adduct, bis(tricyclohexylphosphine)palladium(0),bis(triethylphosphine)palladium(II) chloride,bis(triphenylphosphine)palladium(II) acetate,bis(triphenylphosphine)palladium(II) chloride,bis[tri(o-tolyl)phosphine]palladium(II) chloride,dichlorobis(tricyclohexylphosphine)palladium(II), andtrans-benzyl(chloro)bis(triphenylphosphine)palladium(II), andpalladium(0) catalysts, such astetrakis(triphenylphosphine)palladium(0),bis[1,2-bis(diphenylphosphino)ethane]palladium(0),bis(tri-t-butylphosphine)palladium(0),bis(dibenzylideneacetone)palladium(0) andtris(dibenzylideneacetone)dipalladium(0) (i.e., Pd₂dba₃, in free andsolvate form, e.g., as a chloroform adduct). For example, the palladiumsource can comprise tris(dibenzylideneacetone)dipalladium(0), e.g.,consist or consist essentially oftris(dibenzylideneacetone)dipalladium(0).

In an embodiment, the palladium source comprises palladium(0) or apalladium(II) salt, optionally as complexes (e.g., further comprisingligands). A non-limiting list of palladium sources includes:allylpalladium(II) chloride dimer,bis(acetonitrile)dichloropalladium(II),bis(acetylacetonate)palladium(II), bis(benzonitrile)palladium(II)chloride, bis(dibenzylideneacetone)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II)bromide, tetrakis(acetonitrile)palladium(II) tetrafluoroborate,tris(dibenzylideneacetone)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct, [1,2-bis(diphenylpbosphino)ethane]dichloropalladium(II),1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloridedichloromethane adduct, bis(tricyclohexylphosphine)palladium(0),bis(triethylphosphine)palladium(II) chloride,bis(triphenylphosphine)palladium(II) acetate,bis(triphenylphosphine)palladium(II) chloride,bis(tri-t-butylphosphine)palladium(0),bis[1,2-bis(diphenylphosphino)ethane]palladium(0),bis[tri(o-tolyl)phosphine]palladium(II) chloride,dichlorobis(tricyclohexylphosphine)palladium(II),tetrakis(triphenylphosphine)palladium(0),tetrakis(triethylphosphine)palladium(0), andtrans-benzyl(chloro)bis(triphenylphosphine)palladium(II).

In an embodiment, the palladium source is selected from the groupconsisting of allylpalladium(II) chloride dimer,tris(dibenzylideneacetone)dipalladium(0),tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct,tetrakis(triphenylpbosphine)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II)bromide, and bis(acetonitrile)dichloropalladium(II).

In an embodiment, the palladium source istris(dibenzylideneacetone)dipalladium(0).

In some embodiments, palladium-catalyzed reactions offer ametal-mediated reaction that as compared to a non-metal-catalyzedreaction result in higher yields and/or cleaner formation of desiredproduct(s). Typically, palladium-catalyzed reactions occur with asubstoichiometric amount of both a palladium source and one or morepalladium-binding ligands to facilitate the catalytic cycle.

In some embodiments, palladium-catalysis facilitates the reaction of tworeagents to provide a higher molecular weight product. In someembodiments, the amounts of the two reagents are the same. In someembodiments the amounts of the two reagents are different. In caseswhere the amounts of the two reagents are different, the less abundantreagent is referred to as the limiting reagent.

In some embodiments, the palladium source is present in an amount offrom about 0.2 mole % to about 5 mole % with respect to the compound offormula (III). In some embodiments, the palladium source is present inan amount of from about 0.2 mole % to about 1.5 mole % with respect tothe compound of formula (III). In an embodiment, the palladium source ispresent in an amount of from about 0.5 mole % to about 5 mole % withrespect to the compound of formula (III). In a further embodiment, thepalladium source is present in an amount of from about 0.5 mole % toabout 1.5 mole % with respect to the compound of formula (III). In yetanother embodiment, the palladium source is present in an amount ofabout 1.0 mole % with respect to the compound of formula (III).

In some embodiments, the palladium source is present in about 0.2%,about 0.5%, about 1%, about 2%, about 3%, about 4%, or about 5%palladium on a molar basis compared to the molar amount of the limitingreagent.

In an illustrative example, 2 mol %tetrakis(triphenylphosphine)palladium(0) is 0.02 moles of palladium(0)per mole of the limiting reagent (e.g., a compound of formula (III)). Inanother example, 1 mol % tris(dibenzylideneacetone)dipalladium is 0.02moles of palladium(0) per mole of the limiting reagent.

Palladium-Binding Ligand

The role of the palladium-binding ligand serves to stabilize theintermediate species within the palladium catalysis cycle whilefacilitating the formation of the desired reaction product(s). The molarratio of the ligand to the metal can be modified to optimize reactionconditions, such as rate or yield. In some embodiments the molar ratioof palladium-binding ligand to palladium is in a range of from about 1:1to about 10:1, such as about 1.5:1 to about 5:1, about 1.5:1 to about4:1, about 2:1 to about 4:1, or about 3:1 to about 4:1.

In some embodiments, the palladium-binding ligand is an arsenic-basedligand, such as triphenylarsine.

Ligands that can be used in the disclosed coupling are phosphites orphosphines. Appropriate phosphine ligands include triphenylphosphine,tri-tert-butylphosphine,2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos),2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (XPhos),4,5-bis(diphenyphosphino)-9,9′-dimethylxanthine (Xantphos),1,2-bis(diphenylphosphino)ethane (dppe), and1,3-bis(diphenylphosphino)propane (dppp).

In a preferred embodiment, the ligand is a phosphite ligand.

The palladium-binding ligand can be a phosphite ligand of formula (VI):

whereinR⁷ is, at each occurrence, independently selected from phenylheteroaryl, heterocycyl and C₁₋₆ alkyl, wherein said phenyl, heteroaryl,heterocyclyl, and C₁₋₆ alkyl are optionally substituted with one or moreof halo. C₁₋₆ alkyl, C₁₋₆ alkoxy, or N(R⁹)₂, and wherein said phenyl andheteroaryl are optionally further substituted with a fused C₃₋₆cycloalkyl or C₃₋₆ heterocyclyl;R⁸ is selected from phenyl heteroaryl, heterocyclyl, and C₁₋₆ alkyl,wherein said phenyl, heteroaryl, heterocyclyl, and C₁₋₆ alkyl areoptionally substituted with one or more of halo. C₁₋₆ alkyl, C₁₋₆alkoxy, or N(R⁹)₂, and wherein said phenyl and heteroaryl are optionallysubstituted with a fused C₃₋₆ cycloalkyl or C₃₋₆ heterocyclyl, orR⁸ is

whereinL is selected from the group consisting of —(CH₂)_(n)—,

R⁸ is optionally connected by a bond or —(CH₂)_(n)— to one R⁷ to form aring, or to each R⁷ to form two rings;each R⁹ is C₁₋₆ alkyl, or two R⁹ can combine to form a 3-10 memberedheterocyclyl, wherein heterocyclyl comprises 1-3 nitrogen atoms and isoptionally substituted by Ca alkyl or C(O)—(C₁₋₆ alkyl); andn is 1, 2, or 3.

In another embodiment, R⁷ is, at each occurrence, independently selectedfrom phenyl and C₁₋₆ alkyl, wherein said phenyl and C₁₋₆ alkyl areoptionally substituted with one or more of halo. C₁₋₆ alkyl, C₁₋₆alkoxy, or N(R⁹)₂ and wherein said phenyl is optionally furthersubstituted with a fused cycloalkyl; and

R⁸ is selected from phenyl and C₁₋₆ alkyl wherein said phenyl and C₁₋₆alkyl are optionally substituted with one or more of halo, C₁₋₆ alkyl,C₁₋₆ alkoxy, or N(R⁹)₂, and wherein said phenyl is optionallysubstituted with a fused cycloalkyl, or

R⁸ is

whereinL is selected from the group consisting of —(CH₂)_(n)—,

R⁸ is optionally connected by a bond or —(CH₂)_(n)— to one R⁷ to fort aring, or to each R⁷ to form two rings;each R⁹ is C₁₋₆ alkyl, or two R⁹ can combine to form a 3-10 memberedheterocyclyl, wherein heterocyclyl comprises 1-3 nitrogen atoms and isoptionally substituted by C₁₋₆ alkyl or C(O)—(C₁₋₆ alkyl).

In another embodiment, R⁷ is, at each occurrence, independently phenyl,optionally substituted with one or more of halo, C₁₋₆ alkyl. C₁₋₆alkoxy, or N(R⁹)₂ and wherein said phenyl is optionally furthersubstituted with a fused cycloalkyl; and

R⁸ is phenyl, optionally substituted with one or more of halo. C₁₋₆alkyl, C₁₋₆ alkoxy, or N(R⁹)₂, and wherein said phenyl is optionallysubstituted with a fused cycloalkyl, or

R⁸ is

whereinL is selected from the group consisting of —(CH₂)_(n)—,

R⁸ is optionally connected by a bond or —(CH₂)_(n)— to one R⁷ to form aring, or to each R⁷ to form two rings;each R⁹ is C₁₋₆ alkyl, or two R⁹ can combine to form a 3-10 memberedheterocyclyl, wherein heterocyclyl comprises 1-3 nitrogen atoms and isoptionally substituted by C₁₋₆ alkyl or C(O)—(C₁₋₆ alkyl).

In another embodiment, the palladium-binding ligand is a phosphiteligand selected from the group consisting of:

In some embodiments, the palladium-binding ligand is selected from thegroup consisting of:

In a particular embodiment, the palladium-binding ligand is

In an embodiment, the palladium-binding ligand is present in a molarratio of between about 3:1 and about 10:1 with respect to the palladiumsource. In a further embodiment, the palladium-binding ligand is presentin a molar ratio of about 3:1, about 4:1, about 5:1, about 6:1, about7:1, about 8:1, about 9:1, or about 10:1 with respect to the palladiumsource.

In some preferred embodiments, the palladium-binding ligand is presentin a molar ratio of between about 3:1 and about 6:1 with respect to themolar amount of palladium in the palladium source. In some preferredembodiments, the palladium-binding ligand is present in a molar ratio ofabout 3:1, about 4:1, about 5:1, or about 6:1 with respect to the molaramount of palladium in the palladium source.

In some embodiments, the palladium source and the palladium-bindingligand are included in one reagent as a pre-complexed palladiumcatalyst. In an illustrative example,tetrakis(triphenylphosphine)palladium(0) includes both a palladium(0)source and the palladium-binding ligand triphenylphosphine.

In some embodiments, the palladium source and the palladium-bindingligand comprise two reagents that are added to an admixture. In suchcases, the palladium source and the palladium-binding ligand forms theactive palladium catalyst within the admixture. In a preferredembodiment, the palladium source comprisestris(dibenzylideneacetone)dipalladium(0) and the palladium-bindingligand is

Salt Additive

The reagents of the method disclosed herein can also comprise a saltadditive. The salt additive can be a potassium salt, sodium salt,lithium salt, silver salt, or copper salt. Suitable salts include, butare not limited to, potassium trifluoroacetate, sodium trifluoroacetate,lithium trifluoroacetate, potassium triflate, sodium triflate, lithiumtriflate, silver triflate and copper sulfate.

In an embodiment, the salt is selected from the group consisting ofpotassium trifluoroacetate, sodium trifluoroacetate, lithiumtrifluoroacetate, potassium triflate, sodium triflate, lithium triflate,silver triflate and copper sulfate.

In a particular embodiment, the salt is potassium trifluoroacetate.

In an embodiment, the salt additive is present in a molar ratio ofbetween about 1:1 and about 5:1 with respect to the compound of formula(III). In another embodiment, the salt additive is present in a molarratio of about 1:1, about 2:1 about 3:1, about 4:1 or about 5:1 withrespect to the compound of formula (III). In a particular embodiment,the salt additive is present in a molar ratio of between about 2:1 andabout 3:1 with respect to the compound of formula (III).

Anion (A^(Θ))

A^(Θ), for each occurrence, is independently a pharmaceuticallyacceptable anion. In some embodiments, A^(Θ) is chloride, bromide,iodide, sulfate, bisulfate, tosylate (i.e., tolenesulfanate) mesylate(i.e., methanesulfonate), edisylate, maleate, phosphate (e.g.,monophosphate, biphosphate), ketoglutarate, trifluoroacetate, ortriflate (i.e., tifluoromethanesulfonate). In certain embodiments, A^(Θ)is selected from chloride, acetate, trifluoroacetate and bisulfate(i.e., hydrogen sulfate). In a particular embodiment, A^(Θ) istrituoroecetate or bisulfate (i.e., HSO₄ ⁻). In certain embodiments,A^(Θ) is trifluoroacetate. In certain embodiments, A^(Θ) is bisulfate.

6.1. Definitions

The term “C_(x-y) alkyl” refers to unsubstituted saturated hydrocarbongroups, including straight-chain alkyl and branched-chain alkyl groupsthat contain from x to y carbons in the chain. For example, C₁₋₆ alkylis an alkyl group having one to six carbons.

The term “alkoxy” refers to an alkyl group having an oxygen attachedthereto. Representative alkoxy groups include methoxy, ethoxy, propoxy,tert-butoxy and the like. An “ether” is two hydrocarbons covalentlylinked by an oxygen. Accordingly, the substituent of an alkyl thatrenders that alkyl an ether is or resembles an alkoxy.

The term “C₁₋₆ alkoxy” refers to an alkoxy group having one to sixcarbons.

The term “halo” or “halogen” as used herein refers to F, Cl, Br, or I.

The term “haloalkyl” refers to an alkyl group having one or more. e.g.,one, two, or three, halogens. A “C₁₋₆ haloalkyl” is a haloalkyl with analkyl group having one to six carbons. C₁₋₆ haloalkyls includechloroethyl (ClCH₂CH₂), fluoropropyl (FCH₂CH₂), and trifluoromethyl(CF₃).

The term “alkylidenyl” refers to the radical=CR^(a)R^(b), wherein R^(a)and R^(b) are each independently hydrogen or alkyls.

The term “alkenyl” and “alkynyl” refer to unsubstituted unsaturatedaliphatic groups analogous in length to the alkyls described above, butthat contain at least one double or triple bond, respectively.

The terms “amine” and “amino” are art-recognized and refer to bothunsubstituted and substituted amines and salts thereof, e.g., a moietythat can be represented by the general formulae:

wherein R^(c), R^(d), and R^(e) each independently represent a hydrogen,an alkyl, an alkenyl, —(CH₂)_(m)—R^(f), or R^(c) and R^(d) takentogether with the N atom to which they are attached complete aheterocycle having from 4 to 8 atoms in the ring structure; Rrrepresents an aryl, a cycloalkyl, a cycloalkenyl, a heterocyclyl or apolycyclyl; and m is zero or an integer from 1 to 8. In preferredembodiments, only one of R^(c) and R^(d) is a carbonyl. e.g., R^(c),R^(d), and the nitrogen together do not form an imide. In even morepreferred embodiments, R^(c) and R^(d) (and optionally R) eachindependently represent a hydrogen, an alkyl, an alkenyl, or—(CH₂)_(m)—R_(f). In certain embodiments, the amino group is basic,meaning the protonated form has a pK_(a)≥7.00.

The terms “amide”, “amido”, and “carboxamide” are art-recognized as anamino-substituted carbonyl and includes a moiety that can be representedby the general formula:

wherein R^(c) and R^(d) are as defined above. Preferred embodiment ofthe amide will not include imides which may be unstable.

The term “heteroatom” as used herein means an atom of any element otherthan carbon or hydrogen. Preferred heteroatoms are nitrogen, oxygen,phosphorus, and sulfur.

The term “hydroxyalkyl” refers to an alkyl group having one or more.e.g., one, two, or three, hydroxy (i.e., —OH) substituents.

The term “aminoalkyl” refers to an alkyl group having one or more, e.g.,one, two, or three, amino substituents.

The term “carboxy” or “carboxyl” is art-recognized and refers to —COOH.

The term “carboxyalkyl” refers to carboxy substituents terminated by analkyl group (i.e., an alkyl ester).

The term “urea” as used herein includes a moiety that can be representedby the general formula:

wherein R^(c), R^(d), and R^(e) are as defined above.

The term “aryl” as used herein includes 5-, 6-, and 7-memberedsubstituted or unsubstituted single-ring aromatic groups in which eachatom of the ring is carbon. The term “aryl” also includes polycyclicring systems having two or more cyclic rings in which two or morecarbons are common to two adjoining rings wherein at least one of therings is aromatic, e.g., the other cyclic rings can be cycloalkyls,cycloalkenyls, cycloalkynyls, aryls, heteroaryls, and/or heterocyclyls.Aryl groups include benzene, naphthalene, phenanthrene, phenol, aniline,and the like.

The terms “carbocycle”, “cycloalkyl”, “carbocyclyl”, as used herein,refer to a non-aromatic substituted or unsubstituted ring in which eachatom of the ring is carbon.

The term “C₃₋₆ cycloalkyl” refers to a cycloalkyl having three to sixcarbons in the ring. Illustrative examples include a cyclopropyl (C₃cycloalkyl) and a cyclopentyl (C₅ cycloalkyl).

The term “heteroaryl” includes substituted or unsubstituted aromatic 5-to 7-membered ring structures, more preferably 5- to 6-membered rings,whose ring structures include one to four heteroatoms. The term“heteroaryl” also includes polycyclic ring systems having two or morecyclic rings in which two or more carbons are common to two adjoiningrings wherein at least one of the rings is heteroaromatic, e.g., theother cyclic rings can be cycloalkyls, cycloalkenyls, cycloalkynyls,aryls, heteroaryls, and/or heterocyclyls. Heteroaryl groups include, forexample, pyrrole, furan, thiophene, imidazole, oxazole, thiazole,triazole, pyrazole, pyridine, pyrazine, pyridazine and pyrimidine, andthe like.

Pharmaceutically acceptable salts are known to those of skill in theart. In some of the embodiments described herein, the compounds offormulae (II) and (III) are trifluoroacetate salts.

As used herein, a “protecting group” is a moiety that masks the chemicalreactivity of a functional group during one or more reactions. In anillustrative example, a nitrogen protecting group such astert-butoxycarbonyl (i.e., tert-butyloxycarbonyl, Boc, or BOC) can beintroduced at one step to mask the chemical reactivity of a protectednitrogen during one reaction then removed under acidic conditions toallow the formerly protected nitrogen to undergo reaction, e.g.,alkylation. A protecting group can be any one known in the at, such asthose described in Wuts. P. G. M.; Greene. T. W. Greene's ProtectiveGroups in Organic Synthesis, 4^(th) ed; John Wiley & Sons: Hoboken,N.J., 2007.

Oxygen and nitrogen protecting groups are known to those of skill in theart. Oxygen protecting groups include, but are not limited to, methylethers, substituted methyl ethers (e.g., MOM (methoxymethyl ether), MTM(methylthiomethyl ether). BOM (benzyloxymethyl ether), PMBM or MPM(p-methoxybenzyloxymethyl ether), to name a few), substituted ethylethers, substituted benzyl ethers, silyl ethers (e.g., TMS(trimethylsilyl ether), TES (triethylsilylether), TIPS(triisopropylsilyl ether), TBDMS (t-butyldimethylsilyl ether), tribenzylsilyl ether, TBDPS (t-butyldiphenyl silyl ether), to name a few), esters(e.g., formate, acetate, benzoate (Bz), trifluoroscetate,dichloroacetate, to name a few), carbonates, cyclic acetals and ketals.Nitrogen protecting groups include, but are not limited to, carbamates(including methyl, ethyl and substituted ethyl carbamates (e.g., Troc),to name a few), amides, cyclic imide derivatives. N-alkyl and N-arylamine, benzyl amines, substituted benzyl amines, trityl amines, iminederivatives, and enamine derivatives, for example.

In some embodiments, the oxygen protecting group is a base-labileprotecting group (i.e., one that can be removed under bask conditions),such as a methyl group when used as an ester to protect a carboxylicacid. In some embodiments the oxygen protecting group is an acid-labileoxygen protecting group (i.e., one that can be removed under acidconditions), such as tert-butyl, 4-methoxybenzyl, or triphenyhmethyl. Insome embodiments, the oxygen protecting group is an oxidation-reductionsensitive oxygen protecting group, such as a benzyl ether which isremoved under catalytic hydrogenation conditions. In some embodimentsthe oxygen protecting group is a silyl ether, such as TBDMS, TIPS, orTES, which is removed with nucleophilic fluoride.

In some embodiments, the nitrogen protecting group is a base-labilenitrogen protecting group (i.e., one that is removed under basicconditions), such as 9-fluorenylmethyl carbamate (Fmoc). In someembodiments, the nitrogen protecting group is an acid-labile nitrogenprotecting group (i.e., one that is removed under acid conditions), suchas triphenylmethyl, tert-butyl, tert-butoxycarbonyl,2-trimethylsilylethoxycarbonyl (Teoc), or 4-methoxybenzyloxycarbonyl. Insome embodiments, the nitrogen protecting group is anoxidation-reduction sensitive nitrogen protecting group, such as abenzyl, which can be removed under catalytic hydrogenation conditions.

Exemplary anions include, but are not limited to, carboxylates (e.g.acetate, benzoate, trifluoroacetate), halides (e.g., chloride, bromide,iodide), sulfate (e.g., monosulfate, bisulfate) and phosphate (e.g.monophosphate, biphosphate).

In some embodiments, alkyl groups and groups comprising an alkyl group(e.g., alkoxy, alkanoyl, alkylamino, aminoalkyl, heteroalkyl) comprise1-6 carbon atoms. In some embodiments, aryl groups and groups comprisingaryl groups (e.g., aroyl) comprise 6-12 carbon atoms. In someembodiments, heteroaryl groups and groups comprising heteroaryl groups(e.g., heteroaroyl) comprise 1-10 carbon atoms and 1-4 heteroatomsselected from oxygen, nitrogen and sulfur.

The term “heterocyclyl” refers to heterocyclic groups, and includesclosed ring structures analogous to cycloalkyl groups in which one ormore. e.g., 1, 2 or 3, of the carbon atoms in the ring is an elementother than carbon, for example, nitrogen, sulfur, or oxygen.Heterocyclic groups may be saturated or unsaturated. The termheterocyclic group includes rings which are attached to the corestructure via either a bond to one of the heteroatoms in the ring or abond to one of the carbons in the ring. Heterocyclyl groups include, forexample, piperidine, piperazine, pyrrolidine, morpholine, lactonelactams, and the like.

The term “C₃₋₆ heterocyclyl” refers to a heterocyclyl group having threeto six carbons in the ring. In an illustrative example, atetrahydrofuryl has four carbons in the ring in addition to the oxygen,and is thus a C₄ heterocyclyl.

As used herein, the term “optionally substituted” refers to optionalsubstitution by one or more substituents selected independently from thegroup comprising, for example, alkyl, alkoxy, alkylamino, aminoalkyl,hydroxy, halo, cyano, nitro, carboxyl, carboxyalkyl, amido, urea,cycloalkyl, heterocyclyl (e.g., heterocycloalkyl), aryl and heteroarylsubstituents.

6.2. Abbreviations

AP=4-aminophenol

AUC=are under the curve

BOC=Boc, tert-butyloxycarbonyl, or tert-butoxycarbonyl

DAP=4-(dimethylamino)phenol

DMF=N, N-dimethylformamide

EDTA=ethylenediaminetetraacetic acid

ESI=electron spray ionization

GC=gas chromatography

HPLC=high performance liquid chromatography

HRMS=high resolution mass spectrometry

KTFA=potassium trifluoroacetate

LOD=loss on drying

NMP=N-methylpyrrolidone

NMR=nuclear magnetic resonance

PMB=para-methoxybenzyl, 4-methoxybenzyl, or MPM

Pd₂dba₃=tris(dibenzylidenecetone)dipalladium(0)

TBME=tert-butyl methyl ether, methyl tert-butyl ether, or MTBE

TDAPP=tris(4-(dimethylamino)phenyl) phosphite

THF=tetrahydrofiuan

TFA=trifluoroaceticacid

6.3. Methods of Making

In an aspect, provided herein is a method for preparing a compound offormula (II), or a salt thereof comprising the step of admixing. e.g.,reacting, a compound of formula (II), or a salt thereof, with anucleophile (Nuc) in the presence of reagents comprising:

-   -   (a) a palladium source; and    -   (b) a palladium-binding ligand:        to form a compound of formula (II), or a salt thereof.

In an aspect, provided herein is a method for preparing a compound offormula (II), or a salt thereof,

comprising the step of admixing, e.g., reacting, a compound of formula(III), or a salt thereof,

with a nucleophile (Nuc) in the presence of reagents comprising:(a) a palladium source; and (b) a palladium-binding ligand; to form acompound of formula (II), or a salt thereof, wherein:Nuc is R⁴-M, wherein M is H, a metal cation, a non-metal cation, or lonepair of electrons:R⁴ is the radical resulting from addition of Nuc:LG is a leaving group selected from the group consisting of halo or—OC(O)R₈, wherein R₈ is selected from the group consisting of C₁₋₆-alkyland haloalkyl:R¹ is selected from the group consisting of

Y is selected from the group consisting of:—CH₂—,

R² is hydrogen or alkoxy;R³ is selected from the group consisting of hydrogen and an oxygenprotecting group;Z′ is selected from the group consisting of hydrogen and an oxygenprotecting group;R′ is selected from the group consisting of hydrogen and an oxygenprotecting group; andR″ is selected from the group consisting of hydrogen and a nitrogenprotecting group.

In an embodiment, the step of admixing, e.g., reacting a compound offormula (III) in the presence of reagents comprising (a) a palladiumsource and (b) a palladium-binding ligand forms a palladium pi-allylintermediate.

In some embodiments, a compound of formula (II) is a compound of formula(IIa).

In some embodiments, a compound of formula (III) is a compound offormula (IIIa).

In another aspect, provided herein is a method for preparing a compoundof formula (IIa), or a salt thereof:

comprising the step of admixing, e.g., reacting, a compound of formula(IIIa), or a salt thereof,

with the nucleophile (Nuc) having the structure of a compound of formula(X):

in the presence of reagents comprising:(a) a palladium source; and (b) a palladium-binding ligand:to form a compound of formula (IIa), or a salt thereof whereinA^(Θ) is an anion selected from the group consisting of chloride,acetate, trifluoroacetate and bisulfate;LG is a leaving group selected from the group consisting of halo or—OC(O)R₈, wherein R₈ is selected from the group consisting of C₁₋₆-alkyland haloalkyl:R³ is an oxygen protecting group,R′ is an oxygen protecting group;R⁵ is a nitrogen protecting group; andR⁶ is a nitrogen protecting group.

In an embodiment, the step of admixing. e.g., reacting, a compound offormula (Ia) in the presence of reagents comprising (a) a palladiumsource and (b) a palladium-binding ligand forms a pi-allyl (i.e.,π-allyl) intermediate.

In another embodiment of the method, the reagents further comprise (c) asalt additive. In a further embodiment, the salt additive is selectedfrom the group consisting of a potassium salt, sodium salt, lithiumsalt, silver salt, and copper salt. In yet a further embodiment, thesalt additive is selected from the group consisting of potassiumtrifluoroacetate, sodium trifuoroacetate, lithium trifluoroacetate,potassium triflate, sodium triflate, lithium triflate, silver triflateand copper sulfate.

In an embodiment, R′ is tert-butyl: R is 4-methoxy benzyl ether (i.e.,4-methoxybenzyl); R⁵ is tert-butyloxycarbonyl; and R⁶ istriphenylmethyl.

In an embodiment, LG is halo or —OC(O)R₈, wherein R₈ is selected fromthe group consisting of C₁₋₆-alkyl and haloalkyl. In a furtherembodiment, LG is chloride or —OC(O)CF₃.

In an embodiment, the palladium source is selected from the groupconsisting of bis(acetonitrile)dichloropalladium(II),bis(acetylacetonate)palladium(II), bis(benzonitrile)palladium(II)chloride, bis(dibenzylideneacetone)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II)bromide, tetrakis(acetonitrile)palladium(II)tetrafluoroborate,tris(dibenzylideneacetone)dipalladium(0),tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct,[1,2-bis(diphenylphosphino)ethane]dichloropalladium(II),1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloridedichloromethane adduct, bis(tricyclohexylphosphine)palladium(0),bis(triethylphosphine)palladium(II) chloride,bis(triphenylphosphine)palladium(II) acetate,bis(triphenylphosphine)palladium(II) chloride,bis(tri-butylphosphine)palladium(0),bis[1,2-bis(diphenylphosphino)ethane]palladium(0)bis[tri(o-tolyl)phosphine]palladium(II) chloride,dichlorobis(tricyclohexylphosphine)palladium(II),tetrakis(triphenylphosphine)palladium(0),tetrakis(triethylylphosphine)palladium(0), andtrans-benzyl(chloro)bis(triphenylphosphine)palladium(II).

In a further embodiment, the palladium source is selected from the groupconsisting of tris(dibenzylideneacetone)dipalladium(0),tri(dibenzylideneacetone)dipalladium(0)-Chloroform adduct,tetrakis(triphenylphosphine)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II)bromide, and bis(acetonitrile)dichloropalladium(II).

In another embodiment, the palladium source is present in an amount offrom about 0.5 mol % to about 5 mole % with respect to the compound offormula (IIIa).

In an embodiment, the palladium-binding ligand is a phosphite ligand offormula (VI):

whereinR⁷ is, at each occurrence, independently selected from phenyl,heteroaryl, heterocyclyl, and C₁₋₆ alkyl, wherein said phenyl,heteroaryl heterocyclyl, and C₁₋₆ alkyl are optionally substituted withone or more of halo, C₁₋₆ alkyl, C₁₋₆ alkoxy, or N(R⁹)₂, and whereinsaid phenyl and heteroaryl are optionally further substituted with afused C₃₋₆ cycloalkyl or C₃₋₆ heterocyclyl;R⁸ is selected from phenyl, heteroaryl, heterocyclyl, and C₁₋₆ alkyl,wherein said phenyl, heteroaryl, heterocyclyl, and C₁₋₆ alkyl areoptionally substituted with one or more of halo, C₁₋₆ alkyl, C₁ alkoxy,or N(R⁹)₂, and wherein said phenyl and heteroaryl are optionallysubstituted with a fused C₁₋₆ cycloalkyl or C₃₋₆ heterocyclyl, orR⁸ is

whereinL is selected from the group consisting of —(CH₂)_(n)—,

R⁸ is optionally connected by a bond or —(CH₂)_(n)— to one R⁷ to form aring, or to each R⁷ to from two rings;each R⁹ is C₁₋₆ alkyl, or two R⁹ can combine to form a 3-10 memberedheterocyclyl, wherein heterocyclyl comprises 1-3 nitrogen atoms and isoptionally substituted by Ca alkyl or C(O)—C₁₋₆ alkyl; andn is 1, 2, or 3.

In another embodiment, the palladium-binding ligand is a phosphiteligand selected from the group consisting of:

In an embodiment, the palladium-binding ligand is present in a molarratio of between about 3:1 and about 10:1 with respect to the palladiumsource.

In an embodiment, the methods provided herein further comprise the stepof admixing, e.g., reacting, the compound of formula (IIa), or a saltthereof, with a strong acid to form a compound of formula (Va):

wherein A^(Θ) is a pharmaceutically acceptable anion. The strong acidcan be a Bronsted acid (e.g., trifluoroacetic acid, hydrochloric acid),or a Lewis acid (e.g., TiCl₄). In a particular embodiment, the strongacid is trifluoroacetic acid.

In some embodiments, the method comprises the step of isolating thecompound of formula (Va). In some embodiments, the step of isolatingcomprises extracting the admixture with a non-polar solvent, e.g., anaromatic solvent such as toluene, xylenes, or cumene, or a hydrocarbonsolvent, such as pentanes, hexanes, or heptanes, or mixtures of one ormore thereof. In some embodiments, the extracting the admixture with anon-polar solvent is performed at a temperature in a range of from about−25 to about −5° C. In some embodiments, the step of isolating comprisesadding from about 2 to about 6 volumes, e.g., about 2, about 3, about 4,about 5, or about 6 volumes, of a solvent that provides kineticallyfavorable precipitation conditions. e.g., acetonitrile. In someembodiments, the step of isolating comprises filtering the solids toisolate the compound of formula (Va).

In some embodiments the compound of formula (Va) has the structure ofcompound (VII):

In some embodiments, a compound of formula (II), e.g., a compound offormula (IIa), is a compound of formula (IIb), or a salt thereof.

In some embodiments, a compound of formula (III), e.g., a compound offormula (IIIa), is a compound of formula (IIIb), or a salt thereof.

In some embodiments, a nucleophile (Nuc), e.g., a compound of formula(X), has the structure of the nucleophile (UBT).

In another aspect, provided herein is a method for preparing a compoundof formula (IIb), or a salt thereof:

comprising the step of admixing, e.g., reacting, a compound of formula(IIIb), or a salt thereof,

with the nucleophile (UBT):

in the presence of reagents comprising:(a) a palladium source; (b) a palladium-binding ligand; and (c) a saltadditive to form a compound of formula (IIb), or a salt thereof, whereinA^(Θ) is a pharmaceutically acceptable anion;the palladium source is selected from the group consisting oftris(dibenzylideneacetone) dipalladium(0),tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct,tetrakis(triphenylphosphine)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II)bromide, and bis(acetonitrile)dichloropalladium(II):the palladium-binding ligand is selected from the group consisting of

andthe salt additive is selected from the group consisting of potassiumtrifluoroacetate, sodium trifluoroacetate, lithium trifluoroacetate,potassium triflate, sodium triflate, lithium triflate, silver triflate,and copper sulfate.

In an embodiment, the method further comprises the step of admixing,e.g., reacting, the compound of formula (IIb), or a salt thereof, with astrong acid to form a compound of formula (Va):

wherein A^(Θ) is a pharmaceutically acceptable anion.

In certain embodiments of the methods disclosed herein, specificreactants, reagents and/or solvents (e.g., palladium source,palladium-binding ligand, salt additive), and amounts or equivalents, orranges of amounts or equivalents, are selected from Table 1 and Table 2.

Exemplary methods are disclosed in the Examples.

In another aspect, provided herein is a method for preparing a compoundof formula (VIII):

or a salt thereof comprising the step of admixing. e.g., reacting, acompound of formula (IX)

or a salt thereof, with a nucleophile (Nuc)(e.g., R⁴-M) in the presenceof reagents comprising:(a) a palladium source; and (b) a palladium-binding ligand; to form acompound of formula (VI), or a salt thereof.

The nucleophile, palladium source, palladium-binding ligand, andvariables of compounds of formulae (VIII) and (IX) are as defined above.

The compound of formula (VIII) can be converted to a compound of formula(II) via methods described in PCT application, PCT/US2014/027706, whichis hereby incorporated by reference in its entirety.

In some embodiments, the compound of formula (VIII) is a compound offormula (VIIIa).

In some embodiments, the compound of formula (IX) is a compound offormula (IXa).

In another aspect, provided herein is a method for preparing a compoundof formula (VIIIa):

or a salt thereof comprising the step of admixing. e.g., reacting, acompound of formula (IXa)

or a salt thereof, with a nucleophile, e.g., a compound of formula (X):

in the presence of reagents comprising:(a) a palladium source; and (b) a palladium-binding ligand; to form acompound of formula (VIIa), or a salt thereof, whereinA^(Θ) is a pharmaceutically acceptable anion;LG is halo. —O(C═O)N(R¹⁸)₂, —O(C═O)OR¹⁸ or —OC(O)R¹⁸, wherein R¹⁸ isselected from the group consisting of C₁₋₆ alkyl and haloalkyl:R³ is an oxygen protecting group:R⁵ is a nitrogen protecting group; andR⁶ is a nitrogen protecting group.

6.3.1. Solvents

Any organic solvent that does not inhibit the reaction is a suitablesolvent. Suitable solvents include, but are not limited to: N-methylpyrrolidinone, N,N-dimethylformamide. N,N-dimethylacetamide,tetrahydrofuran, methyl tetrahydrofuran, methyl tert-butyl ether,dioxane, acetonitrile, acetone, dichloromethane, propylene carbonate,methanol, ethanol, tert-butanol, tert-amyl alcohol, and any combinationsthereof. In some embodiments, the solvent is tetrahydrofuran. In someembodiments, the solvent is a mixture of tetrahydrofuran and N-methylpyrrolidone.

6.3.2. Temperature

The method for preparing a compound of formula (II), e.g., a compound offormula (IIa), as described herein can be performed at a range oftemperatures. In some embodiments, the temperature at which the compoundof formula (II), e.g., a compound of formula (IIa), is formed is in arange of from about 0 to about 65° C., such as about 10 to about 40,about 15 to about 35, about 20 to about 30, or about 23 to about 30° C.In some embodiments, the temperature at which the compound of formula(II). e.g., a compound of formula (IIa), is formed is at about 0, about10, about 20, about 25, about 30, about 40, about 50, or about 60° C. Insome embodiments, the temperature is ambient temperature in a range offrom about 23 to about 30° C.

6.3.3. Time

The method for preparing a compound of formula (II). e.g., a compound offormula (IIa), as described herein can be performed at various lengthsof time. In some embodiments, the reaction time at which the formationof compound of formula (II). e.g., a compound of formula (IIa), iscompleted is in a range of from about 10 min to about 7 days, such asabout 10 min to about 2 days, about 15 min to about 24 hours, about 30min to about 12 hours, about 1 to about 6 hours, or about 2 to about 5hours. In some embodiments, the reaction time at which the formation ofthe compound of formula (II), e.g., a compound of formula (IIa), iscompleted is at about 0.25, about 0.5, about 1, about 2, about 4, about6, about 8, about 12, or about 24 hours. In some embodiments, thereaction time is about 15 min. In some embodiments, the reaction time isabout 4 hours.

6.3.4. Removal of Palladium

After completion of the reaction, palladium can be removed from thereaction mixture by any method known in the art including but notlimited to adsorption, extraction, and crystallization methods. In anillustrative example, the palladium in solution after reaction can beadsorbed onto activated carbon and then the solution filtered throughperlite for removal of the palladium from the desired organic product.In another example, the reaction mixture can be treated with ascavenging resin, e.g., a thiourea immobilized on a solid support, e.g.,QuadraPure® TU (Johnson Matthey Finland Oy), and then filtered to removethe palladium species.

In some embodiments, following the palladium-mediated coupling, thereaction mixture is subjected to acidic aqueous washes. In someembodiments, the acidic aqueous washes have a pH in the range of fromabout 0.5 to about 2.5. The washes have the primary purpose of removingpalladium from the process stream. This aqueous waste stream contains asignificant majority of the palladium used in the process.

In certain embodiments, treatment of the process stream with adithiocarbamate, e.g., sodium diethyldithiocarbamate or ammoniumpyrrolidinedithiocarbamate, is used to provide a compound of thedisclosure. e.g., a compound of formula (II)(such as a compound offormula (IIa), a compound of formula (IIb)) or a compound of formula(V)(such as a compound of formula (Va), e.g., ceftolozane sulfate), withpalladium levels of 0.001-10 ppm. Typically, the compound of thedisclosure. e.g., ceftolazane TFA, contains about 100 ppm palladium. Toreduce the palladium levels to pharmaceutically acceptable levels, thecompound of the disclosure, e.g., ceftolozane TFA, is first dissolved inan aqueous medium and treated with from about 0.1 to about 10 mole % ofa dithiocarbamate, e.g., sodium diethyldithiocarbamate or sodiumdimethyldithiocarbamate, resulting in a fine slurry ofpalladium-containing solids. These palladium-containing solids arefiltered away from the batch, which undergoes salt exchange by thepreviously reported sequence to provide a compound of formula (Va),e.g., ceftolozane sulfate, with 0.001-10 ppm of residual palladium.

In some embodiments the removal of palladium comprises one or more.e.g., two, three, four, or five, methods that are performed in sequenceto afford a compound of the disclosure containing a residual amount ofpalladium. The methods used can be the same method repeated one or more.e.g., two, three, four, or five, times or a combination of differentmethods. A combination of different methods can be performed in anyorder. In an illustrative example, an acidic aqueous wash of pH 1 of theorganic reaction mixture from the palladium reaction removes about 90%of the palladium used in the reaction. In another illustrative example,an acidic aqueous wash (pH 1), followed by treatment with thedithiocarbamte ammonium pyrrolidinedithiocarbamate (APDTC) andfiltration of the precipitated solids through a 0.4 μm filter, affordsan organic solution comprising the compound of the disclosure, e.g., acompound of formula (II)(such as a compound of formula (IIa), a compoundof formula (IIb)) or a compound of formula (V)(such as a compound offormula (Va)), and <10 ppm palladium.

Subsequent to the methods described herein, a compound of thedisclosure, e.g., a compound of formula (II)(such as a compound offormula (IIa), a compound of formula (IIb)) or a compound of formula(V)(such as a compound of formula (Va)), contains a residual level ofpalladium. In some embodiments, the palladium is present in a range fromabout 0.01 parts per million (ppm) to about 50 ppm palladium, such asabout 0.01 to about 40, about 0.01 to about 30, about 0.01 to about 10,about 0.01 to about 5, about 0.01 to about 3, about 0.01 to about 2,about 0.01 to about 1.5, about 0.01 to about 1, about 0.01 to about 0.5:about 0.02 to about 40, about 0.02 to about 30, about 0.02 to about 10,about 0.02 to about 5, about 0.02 to about 3, about 0.02 to about 2,about 0.02 to about 1.5, about 0.02 to about 1, about 0.02 to about 0.5:about 0.05 to about 40, about 0.05 to about 30, about 0.05 to about 10,about 0.05 to about 5, about 0.05 to about 3, about 0.05 to about 2,about 0.05 to about 1.5, about 0.05 to about 1, about 0.05 to about 0.5;about 0.1 to about 40, about 0.1 to about 30, about 0.1 to about 10,about 0.1 to about 5, about 0.1 to about 3, about 0.1 to about 2, about0.1 to about 1.5, about 0.1 to about 1, about 0.1 to about 0.5; about0.2 to about 40, about 0.2 to about 30, about 0.2 to about 10, about 0.2to about 5, about 0.2 to about 3, about 0.2 to about 2, about 0.2 toabout 1.5, about 0.2 to about 1, about 0.2 to about 0.5: about 0.5 toabout 40, about 0.5 to about 30, about 0.5 to about 10, about 0.5 toabout 5, about 0.5 to about 3, about 0.5 to about 2, or about 0.5 toabout 1.5 ppm palladium. In some embodiments the palladium is present inabout 0.01, about 0.02, about 0.05, about 0.1, about 0.2, about 0.3,about 0.4, about 0.5, about 1, about 1.5, about 2, about 5, about 10,about 20, or about 50 ppm palladium.

6.3.5. Recovery of Palladium

Palladium is an expensive rare earth metal. Spent . . . crude palladiummixtures recovered from the methods of the disclosure can be sold tometal processors for recycling. Recovery of palladium is desirable todefray the overall cost of a large scale manufacturing processcomprising palladium, which involves both the purchase of the palladiumcatalyst but the cost in disposal of palladium-containing waste streams.In some cases, a palladium recovery method is critical to the economy ofthe method of the disclosure.

In some embodiments, the palladium is recovered, for recycling andprocessing after the palladium reaction is completed. In someembodiments, following the palladium-mediated coupling to form acompound of formula (II). e.g., a compound of formula (IIa). e.g., acompound of formula (IIb), the reaction mixture is subjected to acidicaqueous washes in a pH range of from about 0.5 to about 2.5 . . . whichhave the primary purpose of removing palladium from the process stream.In some embodiments, the pH of the acidic aqueous solution is increasedfrom an initial pH in a range of from about 0.5 to about 5.5 to a finalpH in a range of from about 5 to about 10. In some embodiments, anoxidant, e.g., bleach, is added. The recovery process results in theprecipitation of solid palladium-containing solids, which can befiltered away from the solution.

In an example, the combined acidic aqueous layers (pH range of 0.5 to2.5) are distilled (jacket temperature=40° C.) until about 10% of thevolume is removed (the removed solvent being mostly THF). The solutionis treated with NH₄OH until the pH is from about 5 to about 10 (targetpH of about 7.5), while keeping the temperature below 20° C. Thisresults in a dark slurry containing white solids. Following, the batchis treated with 0.4 equivalents (relative to the TATD-CLE input of thebatch) of NaClO (i.e., bleach; 0.1-2 equivalents, with a target of about0.4 equivalents relative to the TATD-CLE input). The solutionimmediately turns red and is stirred for 2 hours at room temperature.Then, cellulose is added to the batch and the slurry is filtered througha pad of cellulose, providing a palladium-rich cake. About 90% of thepalladium initially present in the aqueous solutions is recovered, orabout 80% of the palladium initially used in the process.

6.4. Compositions

In an aspect, provided herein are compositions comprising a compound offormula (Va).

wherein A^(Θ) is a pharmaceutically acceptable anion, prepared accordingto any of the methods described herein. In some embodiments. A^(Θ) ischloride, bromide, iodide, sulfate, toluenesulfonate, methanesulfonate,edisylate, maleate, phosphate, ketoglutarate . . . trifluoroacetate, ortrifluoromethanesulfonate. In some preferred embodiments, A^(Θ) issulfate.

In some embodiments, the compound of formula (Va) has the structure ofcompound (VII):

In an aspect, provided herein are compositions comprising a compound offormula (Vb),

wherein A^(Θ) is a pharmaceutically acceptable anion, prepared accordingto any of the methods described herein.

In some embodiments the composition (e.g., comprising a compound offormula (Va) or a compound of formula (Vb)) comprises palladium. In someembodiments, the palladium is present in a range from about 0.01 partsper million (ppm) to about 50 ppm palladium . . . such as about 0.01 toabout 40, about 0.01 to about 30, about 0.01 to about 10, about 0.01 toabout 5, about 0.01 to about 3, about 0.01 to about 2, about 0.01 toabout 1.5, about 0.01 to abot 1, about 0.01 to about 0.5: about 0.02 toabout 40, about 0.02 to about 30, about 0.02 to about 10 . . . about0.02 to about 5, about 0.02 to about 3, about 0.02 to about 2, about0.02 to about 1.5, about 0.02 to about 1, about 0.02 to about 0.5: about0.05 to about 40, about 0.05 to about 30, about 0.05 to about 10, about0.05 to about 5, about 0.05 to about 3, about 0.05 to about 2, about0.05 to about 1.5, about 0.05 to about 1, about 0.05 to about 0.5: about0.1 to about 40, about 0.1 to about 30 . . . about 0.1 to about 10,about 0.1 to about 5, about 0.1 to about 3, about 0.1 to about 2, about0.1 to about 1.5, about 0.1 to about 1, about 0.1 to about 0.5: about0.2 to about 40, about 0.2 to about 30, about 0.2 to about 10, about 0.2to about 5, about 0.2 to about 3, about 0.2 to about 2, about 0.2 toabout 1.5, about 0.2 to about 1, about 0.2 to about 0.5; about 0.5 toabout 40, about 0.5 to about 30, about 0.5 to about 10, about 0.5 toabout 5, about 0.5 to about 3, about 0.5 to about 2, or about 0.5 toabout 1.5 ppm palladium. In some embodiments, the palladium is presentin about 0.01, about 0.02, about 0.05, about 0.1, about 0.2, about 0.3,about 0.4, about 0.5, about 1, about 1.5, about 2, about 5, about 10,about 20, or about 50 ppm palladium. In some preferred embodiments, thelevel of palladium in the composition is less than the pharmaceuticallyacceptable level of palladium, e.g., as specified in the United StatesPharmacopeia (USP) General Chapter <232> Elemental Impurities—Limits.Revision Bulletin dated Feb. 1, 2013:

TABLE A Elemental Impurities for Drug Products (excerpted from USPChapter <232> Revision Bulletin dated Feb. 1, 2013) ParenteralInhalational Oral Daily Daily Daily LVP^(b) Dose PDE^(a) Dose PDE DosePDE Component Element (μg/day) (μg/day) (μg/day) Limit (μg/g) Palladium100 10 1.5 1.0 ^(a)PDE = Permissible daily exposure based on a 50-kgperson. ^(b)LVP = Large volume parenteral.

TABLE B Default Concentration Limits for Drug Substances and Excipients(excerpted from USP Chapter <232> Revision Bulletin dated Feb. 1, 2013)Concentration Concentration Concentration Limits (μg/g) for Limits(μg/g) for Limits (μg/g) for Oral Drug Parenteral Drug Inhalation DrugProducts with Products with a Products with a a Maximum Maximum MaximumDaily Dose Daily Dose Daily Dose Element of ≤ 10 g/day of ≤ 10 g/day of≤ 10 g/day Palladium 10 1.0 0.15

In some embodiments, the level of palladium is determined in any one ofthe pharmaceutical compositions described herein. For example, the levelof palladium can be measured when the composition is formulated in unitdosage form. e.g., in combination with tazobactam, e.g., in Zerbaxa®.

In another aspect, provided herein is a composition comprising:

(a) a compound of formula (IIIb):

or a salt thereof,(b) the nucleophile of formula (UBT):

(c) a palladium source;(d) a palladium-binding ligand; and(e) a salt additive.

In an embodiment, the palladium source is selected from the groupconsisting of tris(dibenzylideneacetone)dipalladium(0),tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct,tetrakis(triphenylphosphine)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II)bromide, and bis(acetonitrile)dichloropalladium(II).

In an embodiment, the palladium-binding ligand is selected from thegroup consisting of

In an embodiment the salt additive is selected from the group consistingof potassium trifluoroacetate, sodium trifluoroacetate, lithiumtrifluoroacetate, potassium triflate, sodium triflate, lithium triflate,silver triflate, and copper sulfate.

In another embodiment, the composition further comprises a pi-allylintermediate.

In another embodiment, the composition further comprises a compound offormula (IIb):

wherein A^(Θ) is an anion, e.g., a pharmaceutically acceptable anion.

In another embodiment, the salt additive is selected from the groupconsisting of potassium trifluoroacetate, sodium trifluoroacetate, andlithium trifluoroacetate, and the composition further comprises acompound of formula (IIIc).

6.4.1. Pharmaceutical Compositions

A compound as prepared by the method of the disclosure. e.g., a compoundof formula (Va). e.g., compound (VI), can be formulated as apharmaceutical composition. The pharmaceutical composition canoptionally further include a beta-lactamase inhibitor such astazobactam. The pharmaceutical composition can be obtained by processesdescribed herein. In particular, pharmaceutical compositions can beobtained by a process comprising the step of forming an aqueous solutioncontaining the compound of the disclosure. e.g., a compound of formula(Va), and lyophilizing the aqueous solution to obtain a pharmaceuticalcomposition. The aqueous solution may additionally comprise excipients,stabilizers, pH adjusting additives (e.g., buffers) and the like.Non-limiting examples of these additives include sodium chloride, citricacid and L-arginine. For example, the use of sodium chloride can resultin greater stability; L-arginine can be used to adjust pH and toincrease the solubility of ceftolozane; and citric acid can be used toprevent discoloration of the product, due to its ability to chelatemetal ions. In particular, the aqueous solution can include ceftolozanesulfate and additional components such as sodium chloride to stabilizethe ceftolozane, and an alkalizing agent such as L-arginine to provide apH of about 5-7 prior to lyophilization. The pharmaceutical compositionscan be lyophilized (freeze-dried) and stored as a lyophilate for laterreconstitution. Exemplary disclosures relating to lyophilization ofpharmaceutical formulations include Konan et al., Int. J. Pharm. 2002233 (1-2), 293-52; Quintanar-Guerrero et al., J. Microencapsulation 199815 (1), 107-119; Johnson et al., J. Pharmaceutical Sci. 2002, 91 (4),914-922; and Tang et al., Pharmaceutical Res. 2004, 21 (4), 191-200; thedisclosures of which are incorporated herein by reference. As analternative to lyophilization, a pharmaceutical composition can be spraydried, or stored frozen and then thawed, reconstituted, and dilutedbefore administration.

In some embodiments, the pharmaceutical composition of the disclosure.e.g., comprising a compound of formula (Va), e.g., compound (VII), isformulated as a pharmaceutically acceptable salt. The term“pharmaceutically acceptable salt” refers to the relatively non-toxic,inorganic and organic acid addition salts of a compound of formula (Va),e.g., compound (VII). These salts can be prepared in situ during thefinal isolation and purification of the compound, or by separatelyadmixing. e.g., reacting, a purified compound in its free base form witha suitable organic or inorganic acid, and isolating the salt thusformed. Representative salts include the bromide, chloride, sulfate,bisulfate, phosphate, nitrate, acetate, valerate, oleate, palmitate,stearate, laurate, benzoate, lactate, phosphate, tosylate, citrate,maleate fumarate, succinate, tartrate, naphthylate, mesylate,glucoheptonate, lactobionate, laurylsulfonate salts, and amino acidsalts, and the like. See, for example. Berge et al. 1977.“Pharmaceutical Salts,” J. Pharm. Sci. 66: 1-19.

Pharmaceutical compositions of the cephalosporin compounds of thedisclosure, e.g., a compound of formula (Va), e.g., compound (VII), canbe prepared for storage as lyophilized formulations or aqueous solutionsby admixing the pharmaceutically active ingredient having the desireddegree of purity with optional pharmaceutically acceptable carriers,excipients or stabilizers typically employed in the art (all of whichare referred to herein as “carriers”). i.e., buffering agents,stabilizing agents, preservatives, isotonifiers, non-ionic detergents,antioxidants, and other miscellaneous additives. See, Remington'sPharmaceutical Sciences, 16th edition (Osol, ed. 1980).

In some embodiments, buffering agents in amounts ranging from about 2 mMto about 50 mM are used to help to maintain the pH in the range thatapproximates physiological conditions. Suitable buffering agents for usewith the present disclosure include both organic and inorganic acids andsalts thereof, such as citrate buffers (e.g., monosodiumcitrate-disodium citrate mixture, citric acid-trisodium citrate mixture,citric acid-monosodium citrate mixture, etc.), succinate buffers (e.g.,succinic acid-monosodium succinate mixture, succinic acid-sodiumhydroxide mixture, succinic acid-disodium succinate mixture, etc.),tartrate buffers (e.g., tartaric acid-sodium tartrate mixture, tartaricacid-potassium tartrate mixture, tartaric acid-sodium hydroxide mixture,etc.), fumarate buffers (e.g., fumaric acid-monosodium fumarate mixture,fumaric acid-disodium fumarate mixture, monosodium fumarate-disodiumfumarate mixture, etc.), gluconate buffers (e.g., gluconic acid-sodiumglyconate mixture, gluconic acid-sodium hydroxide mixture, gluconicacid-potassium gluconate mixture, etc.), oxalate buffer (e.g., oxalicacid-sodium oxalate mixture, oxalic acid-sodium hydroxide mixture,oxalic acid-potassium oxalate mixture, etc.), lactate buffers (e.g.,lactic acid-sodium lactate mixture, lactic acid-sodium hydroxidemixture, lactic acid-potassium lactate mixture, etc.) and acetatebuffers (e.g., acetic acid-sodium acetate mixture, acetic acid-sodiumhydroxide mixture, etc.). Additionally, phosphate buffers, histidinebuffers and trimethylamine salts such as Tris can be used.

In some embodiments preservatives are added in amounts ranging from0.01%-1% (w/v). Suitable preservatives for use with the presentdisclosure include phenol, benzyl alcohol, meta-cresol, methyl paraben,propyl paraben, octadecyldimethylbenzyl ammonium chloride, benzalconiumhalides (e.g., chloride, bromide, and iodide), hexamethonium chloride,and alkyl parabens such as methyl or propyl paraben, catechol,resorcinol, cyclohexanol, and 3-pentanol.

In some embodiments, isotonifiers sometimes known as “stabilizers” addedto ensure isotonicity of liquid compositions of the present disclosureand include polhydric sugar alcohols, for example trihydric or highersugar alcohols, such as glycerin, erythritol, arabitol, xylitol sorbitoland mannitol. Stabilizers refer to a broad category of excipients whichcan range in function from a bulking agent to an additive whichsolubilizes the therapeutic agent or helps to prevent denaturation oradherence to the container wall. Typical stabilizers can be polyhydricsugar alcohols (enumerated above); amino acids such as arginine lysine,glycine, glutamine, asparagine, histidine, alanine, ornithine,L-leucine, 2-phenylalanine glutamic acid, threonine, etc., organicsugars or sugar alcohols, such as lactose, trehalose, stachyose,mannitol, sorbitol, xylitol ribitol, myoinisitol, galactitol, glyceroland the like, including cyclitols such as inositol; polyethylene glycol;amino acid polymers; sulfur containing reducing agents, such asthiourea, glutathione, thioctic acid, sodium thioglycolate,thioglycerol, α-monothioglycerol and sodium thiosulfate; low molecularweight polypeptides (e.g., peptides of 10 residues or fewer): proteinssuch as human serum albumin bovine serum albumin, gelatin orimmunoglobulins: hydrophilic polymers, such as polyvinylpyrrolidonemonosaccharides, such as xylose, mannose, fructose, glucose;disaccharides such as lactose, maltose, sucrose and trisaccacharidessuch as raffinose; and polysaccharides such as dextran. In someembodiments, stabilizers are present in the range from 0.1 to 10,000weights per part of weight of pharmaceutically active ingredient.

The compositions will usually be supplied as part of a sterile,pharmaceutical composition that will normally include a pharmaceuticallyacceptable carrier. This composition can be in any suitable form(depending upon the desired method of administration). For example, thepharmaceutical composition can be formulated as an aqueous solution andadministered by intravenous injection or intravenous infusion.

Pharmaceutical compositions can include a ceftolozane salt, e.g.,compound (VII), obtained by methods described herein, combined with abeta-lactamase inhibitor, such as tazobactam (CAS #: 89786-04-9),avibactam (CAS #1192500-31-4), sulbactam (CAS #68373-14-8) and/orclavulanic acid (CAS #58001-44-8). The beta-lactamase inhibitor can beincluded in a crystalline or amorphous form, such as a lyophilizedtazobacam or crystalline tazobactam (e.g., U.S. Pat. Nos. 8,476,425 and5,763,603) to obtain the pharmaceutical composition.

Pharmaceutical compositions comprising a compound of formula (Va), e.g.,compound (VII), can be formulated to treat infections by parenteraladministration (including subcutaneous, intramuscular, and intravenous)administration. In one particular embodiment, the pharmaceuticalcompositions described herein are formulated for administration byintravenous injection or infusion. Pharmaceutical antibioticcompositions can include ceftolozane sulfate and stabilizing amount ofsodium chloride (e.g., 125 to 500 mg of sodium chloride per 1,000 mgceftolozane active) in a lyophilized unit dosage form (e.g., powder in avial). The unit dosage form can be dissolved with a pharmaceuticallyacceptable carrier, and then intravenously administered. In anotheraspect, pharmaceutical antibiotic compositions can include ceftolozanesulfate obtained by a process comprising the steps of lyophilizing anaqueous solution containing ceftolozane and a stabilizing amount ofsodium chloride, where the stabilizing amount of sodium chloride isabout 125 to 500 mg of sodium chloride per 1.000 mg ceftolozane activein the aqueous solution prior to lyophilization.

6.5. Methods of Treatment

In one aspect, provided herein is a method for the treatment ofbacterial infections in a mammal, comprising administering to saidmammal a therapeutically effective amount of a pharmaceuticalcomposition comprising a compound of formula (Va), e.g., compound (VII),prepared according to one or more of the methods described herein. Amethod for the treatment of bacterial infections in a mammal cancomprise administering to said mammal a therapeutically effective amountof a pharmaceutical composition comprising ceftolozane sulfate andsodium chloride.

As used herein, a “mammal” can be any mammal such as a mouse, a rat, adog, a cat, a horse, a pig, a cow, or a primate, such as a human. Incertain embodiments the mammal is a human. The mammal can be an adult ora juvenile.

The pharmaceutical composition of a compound of formula (Va). e.g.,compound (VII), can used in combination with metronidazole for thetreatment of complicated intra-abdominal infections caused by thefollowing Gram-negative and Gram-positive microorganisms such as:Escherichia coli (including strains producing CTX-M-14/15 ESBLs),Klebsiella pneumoniae (including strains producing CTX-M-15 ESBLs).Pseudomonas aeruginosa, Enterobacter clocae, Kebsiella oxytoca, Proteusmirabilis, Bacteroides fragilis, Bacteroides ovatus, Bacteroidesthetaiotaomicron, Bacteroides vulgatus, Streptococcus anginosus.Streptococcus constellatus, and Streptococcus salivarius.

The pharmaceutical compositions can used for the treatment ofcomplicated urinary tract infections, including pyelonephritis, with orwithout concurrent bacteremia, caused by the following Gram-negativemicroorganisms: Escherichia coli (including strains resistant tolevofloxacin and/or producing CTX-M-14/15 ESBLs), Klebsiella pneumoniae(including strains resistant to levofloxacin and/or producing CTX-M-15ESBLs), Proteus mirabilis, and Pseudomonas aeruginosa.

The recommended dosage regimen of pharmaceutical compositions comprisinga compound of formula (Va). e.g., compound (VII), prepared by one ormore methods disclosed herein, and tazobactam in an amount providing 1 gof ceftolozane active per 500 mg of tazobactam acid, is 1.5 gadministered every 8 hors by intravenous (IV) infusion over 1 hour inpatients ≥18 years of age. The duration of therapy should be guided bythe severity and site of infection and the patient's clinical andbacteriological progress (e.g., every 8 hours for 4-14 days forcomplicated Intra-Abdominal Infections and 7 days for ComplicatedUrinary Tract Infections, including Pyelonephritis).

7. EXAMPLES

Examples have been set forth below for the purpose of illustration andto describe certain specific embodiments of the invention. However, thescope of the claim is not to be in any way limited by the examples setforth herein. Various changes and modifications to the disclosedembodiments will be apparent to those skilled in the art and suchchanges and modifications may be made without departing from the spiritof the invention and the scope of the claims.

7.1. Example 1: Coupling of TATD-CLE and UBT Via Palladium Catalysis

TATD-CLE (compound 3. FIG. 1A) (5 g gross, 92.3% potency, 4.615 gactive, 6.775 mmol). UBT (compound 4. FIGS. 1A and 1B) (4.029 g, 7.453mmol), and potassium trifluoroacetate (2.061 g, 13.55 mmol) were chargedto the reaction vessel. THF (39.23 mL) was then added, forming anopaque, white suspension. The reaction mixture was stirred for 30minutes at 30° C., remaining a white suspension.Tri(4-(dimethylamino)phenyl) phosphite (238 mg, 0.542 mmol) was added,followed by addition of Pd₂dba₃ (62 mg, 0.068 mmol). The reaction vesselwas evacuated and backfilled with N₂ gas twice, allowing the solvent toboil in the process. Upon stirring, the reaction mixture turned darkpurple and then light greenish yellow, indicating the presence of activecatalyst. The reaction progress was monitored by HPLC sampling everyhour. A typical reaction time at this catalyst loading is about 3.5 to 4hours, as defined by less than 2% remaining of TATD-CLE and/or TATD-TFAwith respect to TATD-QUATE.

The yield of TATD-QUATE by the process described above was about 92-96%.The yield of TATD-QUATE by the process shown in FIG. 1A (compound 5a)was about 63-66%.

In the example above, a transient intermediate of formula (IIIc)(alsoreferred to herein as “TATD-TFA”) was formed. More specifically,TATD-CLE was partially converted to TATD-TFA. However, both TATD-CLE andTATD-TFA were converted to TATD-QUATE.

7.2. Example 2: Coupling of SCLE and UBT Via Palladium Catalysis

SQUATE was formed under coupling conditions similar to those describedin Example 1.

7.3. Example 3: Screening of Catalysts

Several metal complexes were screened for use in the disclosed method.Metal complexes that do not perform well in the disclosed method includeFe₂(CO)₉, Rh(PPh₃)₃Cl, NiCl₂(PPh₃)₂, CuSO₄, AgOTf, Ni(acac)₂,Pt(PPh₃)₂(H₂CCH₂), Ru₄(C₁₀H₁₅)₄Cl₄, and Ir₂(cod)₄C₂.

7.4. Example 4: Synthesis of tris(4-(dimethylamino)phenyl) phosphite(TDAPP), a palladium-binding ligand Step 1: Preparation of4-(dimethylamino)phenol (DAP)

4-aminophenol (21.8 g, 200 mmol, 1.0 equiv) was charged to a 1 L 3-neckround bottom flask and the temperature was adjusted to 20° C. (about 15to 20° C.). Methanol (218 mL, 10 vol.) was charged to the flask andagitated for 15 mm, at about 22° C. (about 20 to 25° C.). The4-aminophenol did not fully dissolve in the MeOH, resulting in asuspension. H₃PO₄ (85%, 2.3 g, 20 mmol, 0.10 equiv) was slowly chargedwhile maintaining the batch temperature at <25° C. The batch temperaturewas adjusted to about 12° C. (10 to 15° C.); then formaldehyde (36-38%aqueous solution, 45.9 mL, 300 mmol, 3.0 equiv) was charged slowly whilekeeping the batch temperature <20° C. The batch was agitated for 30 minat about 22° C. (20 to 25° C.) resulting in a clear, light yellowsolution.

The solvent was then degassed with nitrogen and the reactor was filledwith nitrogen. Pd/C (10% on activated carbon, 4.4 g, 0.2 wt. equiv) wascharged to the batch. The batch was agitated vigorously under 1 atmhydrogen pressure using a balloon at 20 to 25° C. for three hours. Analiquot of the reaction mixture (10 μL) was withdrawn for HPLC analysis.When the amount of aminophenol (AP) was ≤2% with respect to DAP, thereaction is deemed complete. The reaction usually takes 3-5 hours, butcan be stirred overnight at 20 to 25° C. without observation ofdegradation.

The reaction mixture was filtered through a pad of celite (21.8 g, 1.0wt. equiv). The celite pad was washed with methanol (43.2 mL, 2 vol).The batch was concentrated to 4 volumes (86.2 mL) by distillation.Toluene (174.4 mL, 8 vol) was charged followed by the addition of water(130.8 mL, 6 vol). Aqueous 10NaOH (3 mL, 30 mmol, 0.15 equiv) was thenslowly charged, and the batch was agitated for 30 min. The phases wereseparated and the upper organic phase was concentrated under vacuum to 6volumes (130.8 mL). Toluene (86.4 mL, 4 vol) was charged and the batchwas concentrated to 8 volumes (174.4 mL) by distillation. An aliquot ofthe reaction mixture (10 μL) was withdrawn for analysis of the level ofmethanol and water.

Step 2: Preparation of tris(4-(dimethylamino)phenyl) phosphite (TDAPP)

Et₃N (39.03 mL, 280 mmol, 1.40 equiv) was charged to the reactionmixture obtained in step 1. The batch temperature was adjusted to 2° C.(0 to 5° C.). A solution of PCl₃ (7.00 mL, 80 mmol, 0.40 equiv) intoluene (43.2 mL, 2 vol) was slowly charged to the reactor whilemaintaining the reaction temperature <12° C. The reaction is exothermicand the mixture becomes thick. Vigorous stirring was required forefficient mixing. The batch was agitated for 30 minutes at 15° C. (10 to20° C.). An aliquot of the reaction was withdrawn for HPLC analysis. Thereaction is deemed complete when the amount of DAP is ≤2% with respectto TDAPP. TBME (174.4 ml, 8 vol) was charged and the batch was agitatedfor 2 hours at 23° C. (20 to 25° C.) to ensure thorough precipitation ofthe Et₃N.HCl from the solution.

The batch was filtered through a pad of celite (21.8 g, 1 wt.equiv)/silica gel (10.8 g, 0.5 wt. equiv). The pad of celite/silica gelwas washed with TBME (43.2 ml, 2 vol). Precipitation of white crystals(Et₃N.HCl salt) may form in the filtrate. If precipitation occurs, thefiltrate should be filtered through a pad of celite/silica gel.

The batch was concentrated under reduced pressure to 3 volumes (65.4 mL)at 43° C. (40 to 45° C.), 2-Methyl-2-butanol (174.4 mL, 8 vol) wascharged to the batch. A precipitate may form during addition of thealcohol. The batch was then concentrated undereduced pressure to 6 vol(130.8 mL). Next, 2-methyl-2-butanol (43.2 mL, 2 vol) was charged to thebatch. A thick slurry is formed after 2-methyl-2-butanol addition. Analiquot of the batch was removed to determine residual toluene contentby GC-FID. The toluene content may affect the following crystallization.

The batch temperature was adjusted to 63° C. (60 to 65° C.), resultingin a clear solution. The batch temperature was then adjusted to 40-45°C. and seeded with TDAPP seed crystals (200 mg). Following, the batchwas cooled to 20-25° C. and agitated for 2 hours. The batch was filteredand the wet cake was washed with cold 2-methyl-2-butanol (43.2 mL, 2vol). The batch was dried under reduced pressure to obtain TDAPP as awhite solid. A sample was removed to monitor the drying by GC. The batchis deemed dry when the amount of 2-methyl-2-butanol is ≤5,000 ppm.

The overall yield for Steps 1 and 2 was 17.5 g (60% of theoretical),isolated as a white to light yellow solid. The overall purity was 97.8%AUC (by HPLC analysis) and the structure was confirmed by ¹H NMR.

7.5. Example 5: Preparation of Ceftolozane TFA from TATD-CLE

7.5.1. Preparation of TATD-QUATE

7.5.1(a) Equipment

Two 1 L jacketed glass bottom-drain reactors and an internal temperatureprobe were used.

7.5.1(b) Material Chares and Reaction Parameters for the Preparation ofTATD-QUATE

TABLE 1 Materials used during the preparation of TATD-QUATE Process MWEquivalents Step Material (g/mol) or volumes Amount Used  1 THF  72.117.0 vol 420.0 mL  2 UBT 540.66 1.1 mol equiv 52.4 g  2 TATD-CLE* 681.181.0 mol equiv 66.6 g  2 KTFA 152.11 1.5 mol equiv 20.1 g  2 TDAPP 439.490.08 vol 3.10 g  3 THF  72.11 0.5 vol 30.0 mL  5 Pd₂dba₃ 915.70 0.01 molequiv 0.81 g  6 THF  72.11 1.0 vol 60.0 mL 10 EtOAc  88.11 6.0 vol 360.0mL 11 Water  18.02 14.0 vol 600.0 mL 11 NaHSO₄ 120.06 0.5 wt. equiv 42.0g 18 Harborlite 800 114.02 0.08 wt. equiv 4.8 g 19 EtOAc  88.11 0.5 vol30.0 mL *TATD-CLE active amount of 60.0 grams (90.1% potency) was usedfor all volume and molar equivalent calculations.

7.5.1(c) Stepwise Process for the Preparation of TATD-QUATE

-   -   1. Charge THF [tetrahydrofuran] (373.5 g, 420.0 mL, 7.0 volumes)        at 15 to 25° C. to reactor    -   2. Charge UBT (52.4 g, 9.99 mmol, 1.1 equiv), TATD-CLE (66.6 g,        88.1 mmol, 1.0 equiv). KTFA [potassium trifluoroacetate](20.1 g,        132.1 mmol, 1.5 equiv) and TDAPP        [tris(4-(dimethylamino)phenyl)phosphite](3.10 g, 7.0 mmol, 0.08        equiv) to reactor 1.    -   3. Charge THF [tetrahydrofuran](26.7 g, 30.0 mL, 0.5 volumes) to        reactor 1 by spray ball.    -   4. Adjust the batch temperature to 30° C. and agitate the batch        for 30 minutes.    -   5. Charge TDAPP [tris(4-(dimethylamino)phenyl)phosphite] (3.10        g, 7.0 mmol, 0.06 equiv) followed by Pd₂dba₃        [tris(dibenzylideneacetone)dipalladium(0)] (0.81 g, 0.9 mmol,        0.01 equiv) to the batch.    -   6. Charge THF [tetrahydrofuran](53.4 g, 60.0 mL, 1.0 volume) to        reactor 1 by spray ball and stir the batch at 30° C.    -   7. Collect a sample after 4 hours and analyze it for reaction        completion. The reaction is deemed complete when ≤2.0% of        TATD-CLE+TATD-TFA remain with respect to TATD-QUATE.    -   8. If >2.0% of TATD-CLE+TATD-TFA remains with respect to        TATD-QUATE, then the batch should be stirred for an additional        0.5 to one hour and repeat Step 7.

7.5.1(d) Stepwise Procedure for Quench and Aqeuous Work-Up of TATD-QUATE

-   -   9. Cool the batch in reactor 1 to 5 to 15° C.    -   10. Charge EtOAc [ethyl acetate](322.9 g, 360.0 mL, 6.0 volumes)        to the batch in reactor 1, while maintaining the batch        temperature at 2 to 15° C. then cool to 2 to 8° C.    -   11. Prepare an aqueous solution of 5.0% (w/v) sodium bisulfate        [NaHSO₄] in reactor 2 by first dissolving (21.0 g) NaHSO₄ in        water (420.0 mL, 7.0 volumes) and adjust the solution        temperature of 2 to 8° C.    -   12. Charge the batch in reactor 1 to the 5% NaHSO₄ solution        prepared in Step 11 and stir the batch for 25 to 35 minutes,        while maintaining the batch temperature at 2 to 8° C. through        Step 18.    -   13. Discontinue stirring and allow the phases to separate for at        least 20 minutes.    -   14. Separate the lower aqueous layer and transfer it to a        holding tank for disposal.    -   15. Prepare an aqueous solution of 5.0% (w/v) sodium bisulfate        [NaHSO₄] in reactor 1 by first dissolving (21.0 g) NaHSO₄ in        water (420.0 mL, 7.0 volumes) and adjust the solution        temperature to 2 to 8° C.    -   16. Charge the aqueous solution in reactor 1 (step 15) to the        batch in reactor 2 and stir the batch for 25 to 35 minutes.    -   17. Discontinue stirring and allow the phases to separate for 20        to 40 minutes.    -   18. Separate the lower aqueous layer and transfer it to a        holding tank for disposal.    -   19. Filter the organic layer through Harborlite 800 (4.8 g, 0.08        wt. equivalents) or equivalent filtration material to remove        palladium (0).    -   20. Wash the Harborite with EtOAc (26.9 g, 30.0 mL, 0.5 volumes)        and combine organic layers in reactor 2.

7.5.2. Preparation and Isolation of Ceftolozane TFA

7.5.2(a) Material Charges and Reaction Parameters for the Preparation ofCeftolozane TFA (Ceftolozane Trifluoroacetate)

TABLE 2 Materials used during the preparation of ceftolozane TFA crudeProcess Molar equivalents Step Material MW (g/mol) or volumes AmountUsed 22 Anisole 108.14  1.5 vol  90.0 mL 25 CF₃CO₂H 136.01  4.5 vol270.0 mL 29 Toluene  92.14 10.0 vol 600.0 mL 33 ACN  41.05  1.5 vol 75.0 mL 34 MTBE  88.15 10.0 vol 600.0 mL 36, 37 MTBE  88.15  5.0 vol300.0 mL

7.5.2(b) Stepwise Process for the Preparation of Ceftolozane TFA

-   -   21. Reduce the volume of the batch in reactor 2 by vacuum        distillation to 4.0 volumes (240.0 mL), while maintaining the        batch temperature at <20° C. during distillation.    -   22. Charge anisole (89.6 g, 90.0 mL, 1.5 volumes) to reactor 2.    -   23. Reduce the batch volume in reactor 2 by vacuum distillation        to 3.5 volumes (210.0 mL), while maintaining the batch        temperature at <20° C.    -   24. Cool the batch to <10° C.    -   25. Charge CF₃CO₂H (402.0 g, 240.0 mL, 4.5 volumes) slowly,        while maintaining the batch temperature at <20° C.    -   26. Stir the batch at 18 to 22° C. for 4 to 10 hours. The        temperature should be continuously monitored. A recommended        monitoring interval is 1 hour.    -   27. Collect a sample after 4 hours and analyze it for reaction        completion. The reaction is deemed complete when ≤2.0% of        Ceftolozane t-butyl ester remains with respect to Ceftolozane        (see, e.g., FIG. 3).    -   28. If ceftolozane t-butyl ester is >2.0%, continue the reaction        for 0.5 to 1 hour and repeat Step 27.    -   29. Charge toluene (522.0 g, 600.0 mL, 10.0 volumes) to reactor        2 and adjust the batch temperature to −15° C.    -   30. Stir the mixture for 30 to 40 minutes at −15° C.    -   31. Discontinue stirring and allow the phases to separate for at        least 20 minutes.    -   32. Collect the viscous lower phase in reactor 1.    -   33. Charge ACN [acetonitrile](71.1 g, 90.0 mL, 1.5 volumes) to        reactor 1 and adjust the batch temperature to 10 to 20° C.    -   34. Charge MTBE [methyl t-butyl ether](444.2 g, 600.0 mL, 10.0        volumes) to reactor 1 over 30 to 60 minutes (10-20 vol/h), while        maintaining the batch temperature at 15° C.    -   35. Stir the resulting slurry for 2 to 4 hours at 15° C.    -   36. Filter the slurry and wash the cake with MTBE (111.1 g,        150.0 mL, 2.5 volumes).    -   37. Wash the cake a second time with MTBE (111.1 g, 150.1 mL,        2.5 volumes).    -   38. Dry the cake under reduced pressure with a flow of nitrogen.        The drying process is deemed complete when the final LOD [loss        on drying] value is ≤19%. Typically, the batch is dry with a        final LOD of 7.0 to 9.0%.

As used herein, “t-butyl ceftolozane,” “t-butyl ceftolozane ester,” or“t-buty ceftolozane” refer to a compound of formula (INT-Va):

wherein A^(Θ) is a pharmaceutically acceptable anion.

Perhaps owing to the significant increase in yield realized in thepalladium-mediated coupling reaction, previously developed methods ofisolating ceftolozane TFA did not provide an isolable solid.

To improve the isolation, two operations in the process were improvedfollowing the TFA-mediated deprotection reaction. The first was the lowtemperature phase separation; the second was the precipitation ofceftolozane TFA.

Product Extraction—Low Temperature Phase Separation

A low temperature phase separation that can be used to isolateceftolozane TFA consists of diluting the deprotection reaction mixturewith dichloromethane and cooling the batch to −40 to −25° C. Thisprotocol results in a biphasic mixture, where the lower,ceftolozane-rich phase is separated (based on solvent density; measuredusing a mass flow meter) and carried forward in the process. When thisprotocol was applied to the process stream following the palladiummediated coupling significant product losses were realized (10-20% onaverage) due to the distribution of ceftolozane TFA into the upper layerof the biphasic mixture.

To circumvent this issue, a new protocol was developed, as follows. Uponcompletion of the TFA-mediated deprotection reaction, the batch isdiluted with 8-14 volumes of toluene (target of 10 volumes). Theresulting biphasic mixture is then cooled to a temperature in the rangeof from about

−25 to about −5° C., resulting in a biphasic mixture with a phaseseparation that is easily visualized (i.e., no flow meter is required tomonitor the separation). The lower, ceftolozane-rich phase is easilyseparated from the upper layer, resulting in a significant upgrade inpurity of the process stream. In addition, very little yield loss occursduring this operation, with <1% of the ceftolozane TFA remaining in theupper layer, which is discarded. In addition to toluene, other non-polarsolvents are acceptable, such as hydrocarbon solvents (e.g., pentanes,hexanes heptanes), other aromatic solvents (e.g. xylenes, cumene), andmixtures of one or more thereof.

Isolation—Precipitation of Ceftolozane TFA

When trying to precipitate solid ceftolozane TFA following thepalladium-mediated coupling using known methods, a typical result is theformation of a gel-like substance that could not be filtered or isolatedin a usable fashion. This may be attributed to the propensity ofceftolozane TFA to agglomerate under the isolation conditions, or thepoor stability of the ceftolozane TFA solution during isolation.

These issues are addressed in two ways. First, additional acetonitrile(solvent) is added to the batch prior to the precipitation event. Thisis counterintuitive in that adding additional solvent would nottypically improve a precipitation, as the additional solvent wouldsolubilize the material to be isolated. However, in this case,additional acetonitrile stabilizes the ceftolozane TFA solution duringprecipitation, contributing to an orderly and controlled precipitation.Without wishing to be bound by theory, the addition of acetonitrile isbelieved to provide a solvent mixture exhibiting kinetically favorableconditions for precipitation. Preferably, from about 2 to about 6volumes of acetonitrile present during the precipitation ensure theformation of filterable solids. Since volumes of solvent are typicallydetermined relative to the limiting reagent (in this case. TATD-CLE asshown in Table 1), for each 100 g of limiting reagent, about 200 toabout 600 mL acetonitrile is preferably used for this purpose.

The second protocol change to the isolation is the lowering of theisolation temperature to from about 0 to about 15° C. Subsequent to thelowering of the solution temperature, an antisolvent, such as ahydrocarbon or ethereal antisolvent, e.g., methyl tert-butyl ether, isadded to precipitate the desired product. The decrease in temperature,together with the additional acetonitrile noted above, combines toprovide a controlled and orderly precipitation of highly-filterablesolids, without the formation of gel-like materials, thus maximizing theisolated yield of ceftolozane TFA upon filtration.

7.5.3. Notes

The overall yield for the process was 78% (46.4 g active, 85.9 g total),isolated as a light tan to yellow solid. The overall purity was 90.0%AUC (“area under the curve” measurement), with a weight assay of 52.0%.The identity of the product can be confirmed by comparison to areference NMR spectrum of ceftolozane TFA such as that shown in FIG. 4.

All molar equivalents and volumes (mL/g) are relative to the amount ofactive of TATD-CLE.

All reactions were performed under nitrogen atmosphere. The molar yieldof Ceftolozane TFA is 78%. The molecular weight of Ceftolozane TFA iscalculated without a counter ion.

Storage of Product and Stability: The material was stored at −20° C. ina clear glass container. No degradation was observed under theseconditions, as determined by HPLC analysis.

Cleaning Procedure: Reactors were typically cleaned with water, thenacetone, followed by acetone boil out and drying. The reactor thenappeared to be clean by visual inspection.

7.5.4. Analytical Methods and Chromatograms

TABLE 3 In-Situ Monitoring Process Analytical Preferred Step AnalyticalTest Method Composition  7 Reaction progress TATD- HPLC ≤2.0% CLE andTATD-TFA to TATD-QUATE (3-5 h) 27 Consumption of t-Butyl HPLC ≤2.0%Ceftolozane TFA (4-8 h) 38 Monitor residual volatiles HPLC LOD value ≤19% during Ceftolozane TFA drying

TABLE 4 Analytical Testing for Process Characterization ProcessAnalytical Step Analytical Test Method  1 Water content of THF inreactor Karl Fischer titration  2 Water content of potassiumtrifluoroacetate Karl Fischer titration 14 Residual TATD-QUATE in firstaqueous layer HPLC 17 Residual TATD-QUATE in second aqueous layer HPLC20 Solution yield of TATD-QUATE in final EtOAc HPLC layer 20 % Peak areaanalysis of TATD-QUATE final HPLC EtOAc layer 20 Water content of finalethyl acetate solution Karl Fischer titration 22 GC Analysis forresidual ethyl acetate in final GC anisole solution of TATD-QUATE 31Ceftolozane concentration in toluene layer HPLC 34 Ceftolozaneconcentration in MTBE layer before HPLC filtration 38 Residual palladiumin ceftolozane TFA isolated intermediate 38 Residualdibenzylideneacetone (dba) in ceftolozane TFA isolated intermediate 38Residual TDAPP in ceftolozane TFA isolated intermediate 38 Residual DAPin ceftolozane TFA isolated intermediate 38 Total phosphorus content inceftolozane TFA isolated intermediate 38 Residual BHT in ceftolozane TFAisolated intermediate

The sampling plan of Table 4 was used for process characterization.These analytical tests were not required during process validation andsubsequent commercial production, but was used for investigation and/oradditional process characterization.

7.6. Example 6: Preparation of Ceftazidime

The below experimental protocols (compound 1taz→compound 3taz, andcompound 3taz→compound 5taz) demonstrate an approach to the antibioticceftazidime using the palladium catalysis technology described above.The key transformation is compound 3taz→compound 5taz, where compound5taz was ceftazidime containing conventional protecting groups. Astandard chemical deprotection of compound 5taz would provideceftazidime.

7.6.1. Preparation of Compound 3Taz

A solution of 1taz (3.98 g, 12.08 mmol) in dimethylacetamide (26.7 mL)was treated with methanesulfonyl chloride (1.87 mL, 24.16 mmol) at 0° C.Potassium carbonate (1.67 g, 12.08 mmol) was added and the reactionmixture was stirred at 0° C. After 2 h, EtOAc was charged to thereaction mixture followed by an aqueous solution of 2.4% HCl. Theaqueous layer was removed and discarded and the remaining organic layerwas washed with a 10% (w/v) solution of NaCl. The aqueous layer wasremoved and discarded, and the organic layer was slowly added to asolution of 2 (ACLE.HCl, 4.45 g, 10.98 mmol) in H₂O (13.4 mL) and EtOAc(13.4 mL) at 0° C. The pH was maintained between 3.2-3.8 using asolution of triethylamine (3.83 mL) in EtOAc (5.78 mL). Once theaddition was finished, the reaction mixture was stirred at 0° C. for 30mins until the reaction was complete, as indicated by HPLC analysis.Solid NaCl (0.445 g) was added to the reaction, which was stirred for 20minutes. The reaction mixture was then filtered, and the organic layerwas separated and washed with 20% (w/v) NaCl. The organic layer wasdried (NaSO₄), concentrated and the residue purified by chromatographyon SiO₂ (7:1 EtOAc/Hexane) to provide taz as a white solid. ¹H NMR(CDCl₃, 400 MHz) 7.95 (s, 1H), 7.35 (d, 2H, J=8.8 Hz), 6.94 (s, 1H),6.90 (d, 2H, J=8.8 Hz), 6.32 (s, 2H), 5.99 (d, 1H, J=5.2 Hz), 5.27 (d,1H J=11.6 Hz), 5.20 (d, 1H, J=11.6 Hz), 5.05 (d, 1H, J=4.8 Hz), 4.55 (d,1H, J=12.0 Hz), 4.45 (d, 1H, J=12.0 Hz), 3.81 (s, 3H), 3.65 (d, 1H,J=18.0 Hz), 3.48 (d, 1H, J=18.0 Hz), 1.63 (s, 3H), 1.60 (s, 3H), 1.42(s, 9H); HRMS ESI m/z calcd for C₂₉H₃₅ClN₅O₈S₂ 680.1537 [M+H]⁺, found680.1577.

An HPLC chromatograph of compound 3taz is shown in FIG. 5.

7.6.2. Preparation of Compound 5taz

To a solution of 3taz (0.250 g, 0.371 mmol) in THF (2.15 mL) was addedKTFA (potassium trifluoroacetate, 0.085 g, 0.556 mmol), pyridine (0.033mL, 0.408 mmol), 4-phos (0.013 g, 0.030 mmol) and Pd₂dba₃ (0.003 g,0.004 mmol) at 30° C. After 15 min, HPLC analysis indicated 99%conversion (FIG. 5 and FIG. 6). The reaction mixture was filtered toafford a yellow solution of 5taz. ¹H NMR (CD₃OD, 400 MHz) δ 9.01 (d, 2H,J=6.0 Hz), 8.61 (t, 1H, J=7.8 Hz), 8.10 (dd, 2H, J=6.8, 7.6 Hz), 7.34(d, 2H, J=8.8 Hz), 6.89 (d, 2H, J=8.8 Hz), 6.85 (s, 1H), 5.98 (d, 1H,J=4.8 Hz), 5.74 (d, 1H, J 14.8 Hz), 5.40 (d, 1H, J=14.8 Hz), 5.26 (dd,2H, J=12, 21.2 Hz), 5.25 (d, 1H, J=5.2 Hz), 3.79 (a, 3H), 3.70 (d, 1H,J=18.4 Hz), 3.40 (d, 1H, J=18.4 Hz), 1.54 (s, 3H), 1.53 (s, 3H), 1.45(s, 9H); ³C NMR (CD₃OD. 101 MHz) δ 175.20, 171.41, 165.60, 165.21,162.93, 161.61, 149.69, 147.64, 146.00, 142.92, 131.90, 131.11, 129.65,127.89, 121.76, 114.98, 111.65, 84.24, 83.20, 69.84, 62.21, 60.74,59.29, 55.76, 28.22, 27.40, 24.59, 24.49: HRMS ESI m/z calcd forC₃₄H₃₉N₆O₈S₂ 723.2265 [M]⁺, found 723.2233.

An HPLC chromatograph of the reaction forming compound 5taz fromcompound 3taz is shown in FIG. 6.

7.7. Example 7: Aqueous Workup to Remove Palladium

Upon completion of the palladium-mediated coupling reactions describedabove, the aqueous workup was used to reduce the level of Pd remainingin the product stream. Examples of this include:

1. Dilute the reaction mixture with 7 volumes of ethyl acetate. Wash theresulting slury for 30 minutes with 7 volumes of a 5% aqueous solutionof EDTA. The Pd content of the organic layer is reduced from 461 ppm to370 ppm.

2. Dilute the reaction mixture with 7 volumes of ethyl acetate. Wash theresulting slurry for 30 minutes with 7 volumes of a 5% aqueous solutionof citric acid. The Pd content of the organic layer is reduced from 461ppm to 208 ppm.

3. Dilute the reaction mixture with 7 volumes of ethyl acetate. Wash theresulting slurry for 30 minutes with 7 volumes of a 1 N aqueous solutionof trifluoroacetic acid. The Pd content of the organic layer is reducedfrom 700 ppm to 237 ppm.

4. Dilute the reaction mixture with 7 volumes of ethyl acetate. Wash theresulting slurry for 30 minutes with 7 volumes of a 5% aqueous solutionof sodium chloride. Treat the organic layer with 13 weight % Darco G-60activated charcoal for 30 minutes. The Pd content of the organic layeris reduced from 461 ppm to 269 ppm.

5. Ceftolozane TFA (100.0 g free base equivalent, 1 equiv) with about100 ppm palladium level is charged in one portion to 2 liters of waterand the batch is stirred for 30 minutes, resulting in a brown solutionwith a pH of about 1.6. Subsequently, a 5% ammonium hydroxide solution(165-170 mL) is added to the batch until the pH of the solution is 6.0to 7.0, with a target pH of about 6.5. After reaching the target pH, a5% aqueous solution of sodium diethyldithiocarbamate is charged. Thesolution is prepared by dissolving sodium diethyldithiocarbamatetrihydrate (0.5 g, 0.5% weight/weight compared with ceftolozane freebase) in water (95.0 g, 9.5 mL). The batch is then stirred for 30 to 60minutes (target time of 45 minutes) and filtered through a 0.4 micronfilter to remove palladium-containing solids. Following, the batch istreated with 15% hydrochloric acid (105 mL) until the pH of the solutionis 1.2 to 2.0 (target pH of 1.5). The batch is then stirred for 20 to 40min (target of 30 min) and filtered using a 0.2 micron filter to removepalladium-containing solids. The resulting solution comprisingceftolozane and a residual palladium level of 0.001-10 ppm is thenconverted as previously described to ceftolozane sulfate having the sameresidual level of palladium.

8. EQUIVALENTS AND INCORPORATION BY REFERENCE

All publications, patents, patent applications and other documents citedin this application are hereby incorporated by reference in theirentireties for all purposes to the same extent as if each individualpublication, patent, patent application or other document wereindividually indicated to be incorporated by reference for all purposes.

While various specific embodiments have been illustrated and described,it will be appreciated that various changes can be made withoutdeparting from the spirit and scope of the invention(s).

What is claimed is:
 1. A process for preparing a compound of the formula(IIa):

wherein A^(Θ) is a pharmaceutically acceptable anion, selected from thegroup consisting of chloride, bromide, iodide, sulfate, bisulfate,toluenesulfonate, methanesulfonate, edisylate, maleate, monophosphate,biphosphate, ketoglutarate, trifluoroacetate, andtrifluoromethanesulfonate; comprising the step of admixing a compound ofthe formula (IIIa), or a salt thereof,

with a compound of the formula (X):

wherein: R′ is tert-butyldimethylsilyl, tert-butyl, 4-methoxybenzyl,2-methoxybenzyl, or triphenylmethyl; R³ is tert-butyldimethylsilyl,tert-butyl, 4-methoxybenzyl, 2-methoxybenzyl, or triphenylmethyl; R⁵ istriphenylmethyl, tert-butyl, tert-butoxycarbonyl,2-trimethylsilylethoxycarbonyl, or 4-methoxybenzyloxycarbonyl; R⁶ istriphenylmethyl, tert-butyl, tert-butoxycarbonyl,2-trimethylsilylethoxycarbonyl, or 4-methoxybenzyloxycarbonyl; and LG ishalo or —OC(O)R¹⁸, wherein R¹⁸ is selected from the group consisting ofC₁₋₆ alkyl and C₁₋₆ haloalkyl; in the presence of reagents comprising:(a) a palladium source, wherein the palladium source is selected fromthe group consisting of: bis(acetonitrile)dichloropalladium(II),bis(acetylacetonate)palladium(II), bis(benzonitrile)palladium(II)chloride, bis(dibenzylideneacetone)palladium, allylpalladium(II)chloride dimer, palladium(II) acetate, palladium(II) trifluoroacetate,palladium(II) chloride, palladium(II) bromide,tetrakis(acetonitrile)-palladium(II)tetrafluoroborate,tris(dibenzylideneacetone)dipalladium(0),tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct,[1,2-bis(diphenylphosphinoethane] dichloropalladium(II),1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloridedichloromethane adduct, bis(tricyclohexylphosphine)palladium(0),bis(triethylphosphine)palladium(II) chloride,bis(triphenylphosphine)palladium(II) acetate,bis(triphenylphosphine)palladium(II) chloride,bis(tri-t-butylphosphine)palladium(0),bis[1,2-bis(diphenylphosphino)ethane]palladium(0),bis[tri(o-tolyl)phosphine]palladium(II) chloride,dichlorobis(tricyclohexylphosphine)palladium(II),tetrakis(triphenylphosphine)palladium(0), andtrans-benzyl(chloro)bis(triphenylphosphine)palladium(II); and (b) apalladium-binding ligand selected from the group consisting of:

to provide the compound of formula (IIa), or a salt thereof.
 2. Theprocess of claim 1, wherein: R′ is tert-butyl; and R³ is4-methoxybenzyl.
 3. The process of claim 1, wherein: R⁵ istert-butyloxycarbonyl; and R⁶ is triphenylmethyl.
 4. The process ofclaim 1, wherein LG is chloro or —OC(O)CF₃.
 5. The process of claim 1,wherein A^(Θ) is selected from chloride, acetate, trifluoroacetate andbisulfate.
 6. The process of claim 1, wherein A^(Θ) is trifluoroacetateor bisulfate.
 7. The process of claim 1, wherein A^(Θ) istrifluoroacetate.
 8. The process of claim 1, wherein the palladiumsource is selected from the group consisting of:tris(dibenzylideneacetone) dipalladium(0),tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct,tetrakis(triphenylphosphine)palladium, palladium(II) acetate,palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II)bromide, and bis(acetonitrile)dichloropalladium(II).
 9. The process ofclaim 1, wherein the palladium source istris(dibenzylideneacetone)dipalladium(0).
 10. The process of claim 1,wherein the palladium-binding ligand is selected from the groupconsisting of:


11. The process of claim 1, wherein the palladium-binding ligand is:


12. The process of claim 1, wherein the step of admixing a compound offormula (IIa) in the presence of reagents comprising (a) a palladiumsource and (b) a palladium-binding ligand forms a pi-allyl intermediate.13. The process of claim 1, wherein the palladium-binding ligand ispresent in a molar ratio of between about 1:1 to about 10:1 with respectto the molar amount of palladium in the palladium source.
 14. Theprocess of claim 1, wherein the palladium-binding ligand is present in amolar ratio of between about 3:1 and about 10:1 with respect to themolar amount of palladium in the palladium source.
 15. The process ofclaim 1, wherein the palladium-binding ligand is present in a molarratio of between about 4:1 and about 10:1 with respect to the molaramount of palladium in the palladium source.
 16. The process of claim 1,wherein the palladium-binding ligand is present in a molar ratio ofbetween about 5:1 and about 10:1 with respect to the molar amount ofpalladium in the palladium source.
 17. The process of claim 1, whereinthe palladium-binding ligand is present in a molar ratio of betweenabout 6:1 and about 10:1 with respect to the molar amount of palladiumin the palladium source.
 18. The process of claim 1, wherein thepalladium source is present in an amount of from about 0.2 mole % toabout 5 mole % with respect to the compound of formula (IIIa).
 19. Theprocess of claim 1, wherein the palladium source is present in an amountof from about 0.5 mole % to about 5 mole % with respect to the compoundof formula (IIIa).
 20. The process of claim 1, further comprising thestep of removing the palladium by washing with an aqueous acidicsolution after forming the compound of formula (II).
 21. The process ofclaim 20, further comprising the step of recovering the palladium, afterthe step of removing the palladium, by increasing the pH of the aqueousacidic solution and adding an oxidant to the aqueous acidic solution,thereby recovering the palladium.
 22. The process of claim 1, whereinthe reagents further comprise (c) a salt additive which is selected fromthe group consisting of potassium trifluoroacetate, sodiumtrifluoroacetate, lithium trifluoroacetate, potassium triflate, sodiumtriflate, lithium triflate, silver triflate and copper sulfate.
 23. Theprocess of claim 1, wherein the reagents further comprise (c) a saltadditive which is potassium trifluoroacetate.
 24. The process of claim1, further comprising the step of admixing the compound of formula(IIa):

wherein A^(Θ) is a pharmaceutically acceptable anion, selected from thegroup consisting of chloride, bromide, iodide, sulfate, bisulfate,toluenesulfonate, methanesulfonate, edisylate, maleate, monophosphate,biphosphate, ketoglutarate, trifluoroacetate, andtrifluoromethanesulfonate; with a strong acid selected fromtrifluoroacetic acid and hydrochloric acid, to form an admixturecomprising a compound of formula (Va):

wherein A^(Θ) is trifluoroacetate or chloride.
 25. The process of claim24, further comprising the step of isolating the compound of formula(Va) wherein A^(Θ) is trifluoroacetate or chloride comprising the stepsof: (a) extracting the admixture with a non-polar solvent; and (b)adding from about 2 to about 6 volumes of acetonitrile to isolate thecompound of formula (Va).
 26. The process of claim 24, wherein thestrong acid is trifluoroacetic acid, and wherein the compound of formula(Va):

A^(Θ) is trifluoroacetate.
 27. The process of claim 26, furthercomprising the step of isolating the compound of formula (Va) whereinA^(Θ) is trifluoroacetate comprising the steps of: (a) extracting theadmixture with a non-polar solvent; and (b) adding from about 2 to about6 volumes of acetonitrile to isolate the compound of formula (Va). 28.The process of claim 27, further comprising the step of filtering thesolids to isolate the compound of formula (Va) wherein A^(Θ) istrifluoroacetate.